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and therefore if Spirigera he retained at all it must be for that
section. He refers to his "Prodrome" for a list of the species,
.and we have thus only to examine this list in order to ascertain
his idea of the extent of the genus. They are the following,
taking them in the order in which they are published :

* '< Le type est T. eoncentrica de Buch. Toutes lee eap^ees avec leur synoDjmM
Ae trouvent dans ootre Pradrotne de paUoniologie ttratigraphique!*



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E. Billings on the Oenus Athyris. 53

8» CereSy vultur^ Cirte^ passer, Hereulea^ harpya^ Hecate, iutnida, con-
eenirica, Helmerseni^ Puschana^ dectissata, plebeia, Ferronesensis, Ez"
guerra, Hispanica, Tareno, subconcentricay Pelapayensis, Campomanensis^
Mayendorfi, Boissyi^ serpentina^ lameliosa, amH^tia, Blodena, piano-
sukata^ expansa, pentaedra, pectinifera, trigonella, quinquecostataj quad"
rieosiata, trieosiata and cristigaUi,

Several of the above species do not belong to the group. This
list shows that D'Orbigny regarded the genus as including not
only the types of Athyris and Spirigera but also that of the genus
Merista {M, Herculea) which I shall notice farther on. I think
it quite certain that had D'Orbigny been aware that the genus
was capable of subdivision, he would have retained Athyris for
one of the groups which have the beak imperforate, indeed,
according to the laws of nomenclature, he could not have done
otherwise with any probability of producing a permanent classi-
fication.

In a valuable paper, read before the Geological Society of
France, in May, 1§48, on the Brachiopoda of the Upper Silurian
rocks of England,''^ Mr. Davidson made the following observa-
tions on D'Orbigny's genus :

Vient enauite le genre Spirigera que le m^me auteur 6tablit pour left
coquilles qui poasSdent des epires internes places de la m^me manier^
que les Spirifer, mais qui ont des appendices et des details d'organisation
essentiellement diff6rents. Ces especes, parmi lesquelles nous trouvona
les Terehratula, tumida, Circe^ concentrica, subconcentrica, Roissyi^ pectin^
ifera, ambigua, Helmerseni, Pelapayensis, Campomanensis, Ferronesensis^
Ezquerra, ffispanica^ ont d6j& et6 distingu^es par M. de Verneuil coramer
devant former une section k part, qu'il a nomm6e ]a section des Concen-
trices. Je suis de I'opinion de M. d'Orbignj qu'elles doivent constituer un
genre. L'6tude minutieuse que M. Bouchard a faite de la Terebratula
concentrica ne m'en laisse aucun doute ; mais ce genre n'ayant pas en-
core 6t6 convenablement caract6ris6, je m^abstiendrai de I'adopter dans
oe petit m^moire qui n^est pour ainsi dire qu'un r^um^ d^un plus grand
travail que je publie en ce moment dans le London Geological JoumaL

Upon the above I shall only remark that it is quite clear
that Mr. Davidson then regarded S. concentrica and A, tumida as
congeneric; and that whatever new genus might be established,
it would include both species.

In 1862, McCoy, in the 2nd Fasciculus of the ''British Paleo-
zoic Fossils," page 196, re-defined Athyris as follows: —

** Gen. Ck — Nearly orbicular or ovate, both valves convex ; no cardi*
nal area, foransen, or binge-line : spiral appendages to beak of entering
valve very large, nearly filling the shell ; a strong mesial septum in the
rostral part of entering valve ; dental lamellse moderate; tissue of shell
apparently fibrous.

* Mimoire tur Ue Brachiopodie du Sytthne SiltdtUn supSrieur d^Angleterre, par
M. Th. BavidMD, Boll. GeoL Soc. Fr., v, pp. 809, 814.



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54 E. Billings an the Genus Athyris.

''One tpecimen (of A. tumida) ihovs the pallia] and ovarian impres-
■iont to be thick, namerooa, and dichotomising frequently from beak to
^ margin.**

In the work cited and in the 8d Fascicular, we find the fol-
lowing speciea: — A, tumtda, & eancentricOj ambigua^ De Roissyi^
cxpanaa^ globistricUa^ ghbularis, gregaria, paradoxa, peetinifera,
and squamiaera. This shows clearly enough his views of the
extent of the genus, that is to say, that as it was then under-
stood, it included both A. iumida and A. concentrica. In com-
menting on this, Prof Hall says : — " The fact that McCoy cited
this* as an Athyris, no more renders it an Aihyris than it was
made Airypa^ by being thus described by Dalman ; and it was
just as free for the foundation of a genus after the citation of
McCoy as before." This is true enough, in part It was free
for the foundation of a genus until 1863, when Davidson used
it for that purpose ; but since 1858, it has never been free.

The above is quite sufficient to prove my first and second pro-
positions.

I am not aware that anv thing else of much importance, with
the exception of what relates to Merista^ having been published
up to 1868, when Davidson's excellent work, the " Introduction
to the Classification of the Brachiopoda," made its appearance,
in which the genus was first subdivided. But, before entering
upon this, I shall notice the remarks of Prof. Suess, on the ge-
nus Merista.

This genus was proposed by Prof Suess, in 1851, but he did
not then sufficiently characterize it. The following is all that
I can find, relating to it, that was published previously to 1863.

'* Mr. E. Suess commnuicated the results of the investigations on seve-
ral Brachiopods, from the Bohemian transition rocks, which had been
made by him and Mr. Gustos Dormitzer, of Prague. He showed that
some of the forms heretofore referred to Terebratula had no opening in
the beak, for the passage of the muscle of adhesion ; and, also, that the
distribution of their inner organs points to an affinity with the non-at-
tached genus Pentamerus. These inner organs are borne by six parti-
tions in place of a single calcareous loop ; the spiral arms are not un-
reliable.

*^Throuffh the separation of these forms (for which the name Merista
is proposed) from the genus Terebratula^ an apparent contradiction in the
laws of paleontologicaT distribution is solved, since these smooth forms
will now be separated, which have heretofore offered an apparent contra-
diction to the present views of these laws."

Lest I should not have expressed his views rightly in this
free translation, I give the original in the note below.f

• This Jour. II, zxzii, 181.

t " Htrr Eduard Suess theilte die Erfolge der Unter8ucfauii|^ einiger Bracbiopodea
ans dem bobmischeo Uebergangsgebirge mit, die er eemeinschaftlich mit nerrn
CustoB Dormitser in Prag angestellt hatte. £r seigte, dass mehrere bisher za den



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E. BiUings on the Genus Aihyri$. 55

On page 160 of the same work, there are some farther re-
marks on the classification of the brachiopoda, by Prof. Suess,
in which he refers to the genus Meriata. No generic description
is, however, there given. It appears also that it was again
noticed in "Leonhard's Neues Jahrbuch, p. 127, 1854," I
have not, at present, access to that work, and do not know
whether the genus is described there or not : at all events, at
the time Mr. Davidson prepared the English edition of his
** General Introduction," Merista was not understood.

Prof. King in his " Monograph of the Permian fossils of Eng-
land " (1850) proposed to restore the genus Oleiothyris of Phil-
lips, apparently making it partly equal to AthyrU McCk>y. But
the specimen on which this arrangement was founded, was after-
ward shown to Mr. Davidson, and by him identified with T.
scalprum Barrande (now Merista scalprum), while Cleiothyris
was intended by its author as a substitute for Atrypa. (See Da-
vidson's Introduction, p. 85.)

2. Subdivisum of the Genua by Mr. Davidson in 1854, — From
all the facts above given it may be gleaned that in 1858, when
Mr. Davidson was engaged in the preparation of his (General
Introduction, this group of Brachiopoda was known as a single
genus but with two generic names Athyris McCoy, 1844 ; /i^-
rigera D^Orbigny, 1847. Each of these wm intended by its
author to include the whole group. McCoy was under the im-
pression that all the species had the beak imperforate, while
D'Orbigny maintained that they were all perforated. Both
authors were partly wrong and partly right. The genus was
capable of subdivision, but no one had as yet undertaken that
task ; unless indeed, the observations of Prof. King and Suess
can be so construed. With regard to the latter, as the genus
Merista is now well understood and is diflferent from Athyris, it
does not affect the question. Cleiothyris may be considered as
obsolete.

Mr. Davidson in his " General Introduction " in endeavorinff
to reconcile the conflicting nomenclatures of D'Orbigny and
McCoy divided the genus, retaining the name Athyris for " forms
with an apparently imperforate beak or closed foramen, vari-
ously disposed septa and largely developed dental plates." He

Terebrateb gezShlte Formen an ihrer SpitM keine Oeffnang for den Anheftnng*-
mnskel besitzen, und dass aueh die Vertneilung ihrer inneren Organe aof eine Ver-
vandtechaft mit der ebenfalis nicht angehe&ten Qattong Pentamems binweist.
Diese- inneren Orsane werden von 6 Wanden, atatt yon eber ein&chen Ealkschleife
getragen; die Spiralarme selbst sind nicht aufrollbar."

" IHirch daa Lostrennen dieaer Formen, f&r welche der Name MtrUia Torgeeehbi-
een wird, von der Ghittung, Terebratulii, wird zogleich ein scbeinbarer Widerspmch
in den Qeaetzen palaontologischer Verbreitung gehoben, da eben jene glatten Ar-
ten ausgefldneden werden, welche den bisherigen Aniichten iiber diese Oesetce am
achrofistan edtgegengestanden warea"-~t/aAr&«cA der k, k. geologuohm Biickwan'
Mtdtt, Vienna, i^ pt 4, pp. 160, 160. 1851.



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56 £. Billings on the Genus Athyris,

selected two species, "J., tumtda Dal. or Herctdea Barrande,** and
specially named them as the types.

He retained JSpiryera for the group of which & cancenirica is
the type. As to this latter group, by whatever name it may be
hereafter known, its extent will most probably always be that
assigned to it in the work in -question.

The genus Athyris^ however, as there defined, included Merisla,
a circumstance which, however, as I shall presently show, in no
way vitiates the arrangement. In a note, he states, — " before
coming to the above conclusion, I submitted my views to Mr.
Deshayes, Mr. Salter, and others, who seemed to consider that
this mode of compromising the difficnltj could not reasonably
be objected to by the two authors principally concerned nor by
the generality of Paleontologists." Op. cit, p. 86.

Afterward this classification was strongly objected to bv seve-
ral naturalists, who maintained that McCoy had ^' originally and
positively ^' applied the name Athyris to the S. ooncentriod group,
and, therefore, it could not be transferred to the other principal
section. He, therefore, in the French edition of this introducp
tion (1856)j abandoned his first arrangement,* and substituted JUe-
rista and Athyris^ at the same time transferring the latter to jS^
rigera^ as in the extract given in the note below. (Op. cit, p. 101.)

Upon a careful examination of all the circumstances I think
it will be found that according to the laws of nomenclature this
change cannot be sustained. I shall therefore quote some of
those laws and endeavor to apply them to this case.

The first rule reads thus :

'^S. 1. — The Dame originally given by the founder of a groop or the
describer of a species, should be permanently retained, to the excIuaioQ
of all subsequent synonyms."

It seems scarcely necessary to quote such a rule as this. I
only do so in order to make the comment, that it is the most im-
I)ortant of all the laws of nomenclature ; and that its opera-
tion cannot be prevented in any case, by merely technical objec-
tions or by any error in the details of a genenc or specific de-
scription. Provided the original diagnosis contains suflSicient in
substance, to enable the scientific public to identify the groapi
trivial errors, from which the writibgs of no natundist are free^

* " Mais oe moyen terme a 6ti critique par plusieors oatiiralistM qiu out ihmM
Bor oe que le terme Athyrit avut 6tA orig^oairemeDt et positlvemeDt appliqnA pv
son aateur a la 7*. eoncerUrica et sur rimpropri^t^ de raiatre d^ommatioQ poir
dteigner dee coquelles telles que lea T, tumiiht ffereulea^ Ac M. Suen nooa a ift»
form^ (2) qu'U avait, eu 1851, propos6 le nom de Mtriita (8) poor le groupe ra»>
ferment ces deroiera. (TabandoDDe done la propoditioD que TaTaie fidte en 185S, «a
je cooeerre indiffgremment VAthyru McOoy, ou le Spirifftra a'Orlx, pour le T, rantitm
triea ; et MerUta, Saess, pour lea T. tumida, Eirculea, etc (2) NetM /aArfrvcA, ^
82, Janvier, 1864. (8) Jahrb. k, k, geol EeiehnanHaltt ii, iv, 160, 1861. ^' "
encore dans Leonhard^i netnu Jahrhuchf p. 127, 1864."



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E. Billings on the Genus Athyris. 57

will not have any eflfect All that'can be done is to rectify ;
not to destroy. One of the exoeptiona to this rule is thus ex-
pressed in No. 11. " A name may be changed when it implies
a false proposition which is likely to propagate important errors."
According to this exception if the name Athyris should be
applied to the S. concentrica group there is a possibility of its
j&lling into the list of synonyms ; for, although no very impor-
tant error would be superinduced, yet few naturalists can apply
it to shells with a well defined foramen without feeling that such
an application is to some extent, inconsistent with the purity of
scientific nomenclature.

** § 8. — A generic name, when once estahlisbed, should ne^er be can-
celled in any eubfiequent subdiTision of the groap, bat retained in a re-
stricted sense for one of the constituent portions."

" 4. — A generic name should always be retained for tbat portion of
the original genus which was considered typical by tbe author."

This latter rule is preceded by some introductory observa-
tions which should be embodied in it as they in ract form a
part of the rule itself. They are especially applicable to this
case.

" When a genus is subdivided into other genera, tbe original name
should be retained for that portion of it as at first defined. Authors
frequently indicate this by selecting some one species as a fixed point of
reference, which they term the ** type of the genus." When they omit
doing so, it may still in many cases be justly inferred that the first spe-
eies mentioned on the list, if found accurately to ayree with their defini-
tMUy was regarded by them as the type. A specific name, or its syno-
pyms, will also often serve to point out the particular species which by
implication must be regarded as the original type of the genus. In such
cases we are justified in restoring the name of the old genus to its typi-
cal signification, even when later authors ha?e done otherwise."

Now this rule bears directly on the question, because many
naturalists are under the impression that the first species placed
on the list must necessarily be regarded as the type, where the
author is silent on that point. But according to the above (and
common sense), it is only so if found a^cwraiely to agree with the
definition, Spirigera concentrica does not agree either with the
name Athyrie, nor with McCoy's generic description, nor with
his typical figure. Therefore it cannot be arbitrarily selected as
the type, and the name Athyris^ in consequence, retained for
that group. Indeed in many instances it would be impossible
that the first species placed in the genus should be the type, for
the author might not have the true type in the collection under
investigation.

In this instance, as before mentioned, McCoy was preparing
a work exclusively devoted to Carboniferous fossils, among

Am. Jour. Sci.— Second Sbbixs, Vol. XLIV, Na 130.— Jult, 1867.
8



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58 E. Billings on the Crenus Aihyris.

which A. iumida does not occur. Id preparing his description
of the genoB he may, however, have had that species before him,
and its imperforate beak may have had some influence.

§ 5. ^ When the evidence as to the original type is not clear and indis-
putable, then the person who first sabdivides the genos may affix the
original name to any portion of it at his discretion, and no later author
has a right to transfer that name to any other part of the original genus,^

This last paragraph applies as well to the author who first
sabdi Tided the genus as to others. Once a genus is established,
or subdivided, on sound principles, it becomes the property of
science, and the author himself (either of the genus or the subdi'
vision) can make no change. He may amend by striking out
the errors, if any there be, but all that is true must remain.

I think that on a careful study of all the circumstances, it will
be perceived that Mr. Davidson's first adjustment of this question
was the moat wise, the best for the interests of science, and the
most just toward all the parties concerned, that could be devised.
It was not inconsistent with the laws of nomenclature, but in
perfect accordance with them in every particular ; aud^ therefore,
should be retained.

In one respect, however, it has been modified. Aihyris as
first defined by him, included Merisia of Prof. Suess. This was,
no doubt, due to the fact that the characters of this last named
genus were not then accurately known to tlie scientific publia
This makes little difference. Aferista has long since been sepa-
rated, with its type if. Herculea; leaving the other and most
important group for Aihyris with A. tumida for the type.

W ith regard to Spirigera^ I think it can also be retained not-
withstanding the following rule : —

§ " When two authors define and name the same genus, both making
it exactly of the same extent, the latter name should be cancelled in toto^
and not retained in a modified sense.*'

If the name Aihyris had been extremely objectionable, accor-
ding to the 11th rule, Spirigera might have cancelled it alto-
gether. But the true principle of interpreting these laws is,
that where there is any possibility at all of saving the original
name it must be saved, even if the rules be strained to their ut-
most in that direction. The rules cannot be stretched to de-
stroy ;. but they may be strongly bent in the other direction, to
preserve. If a generic name should be appropriate for a large
number of the species of the group to wnich it was originally
applied, and not very objectionable as to a few only, I doubt that
it can be changed. Such was the case with Aihyris when D'Or-
bigny objected to it. More than two-thirds of the species de-
signated by him are imperforate, and he should have retained
the name for these. Some naturalists were, therefore, in favor



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E. Billings an ih^ Genus Athyris. 59

of rejecting Spirigera altogether ; others of retaining it. It is
not, therefore, a case clearly within the rule ; and as there was
much doubt, the best course to take, as soon as it was fpund pos-
sible to do so, was taken by Mr. Davidson. He decided in favor
of preserving the name.

8. Authors who have adopted ths classification. — In 1866, Profes-
sors H. G. Bronn and F. Eoemer, in the third edition of Bronn's
Lethcea Oeognostica adopted Davidson's classification and copied
his diagnosis of both genera in full. They cited A, tumida as
the type of Athyris, " Die typische Art ist Athyris tumida Mc-
Coy. {Atrypa tumida Dalman.) Andere Arten sind A. Herculea
{TerebrcUula Herculea Barrande), A. pseudo-scalprum {Terebratula
pseudo'scalprum Barrande), A, scalprum (Tertbratulk scaiprum
Fred. Eoemer)." Op. cit., p. 831.

They also recognized S. ooncentrica as the type of Spirigera.
"Die typische Art ist Sp. concentrica {Terthratula concentrica
Bronn). Andere Arten sind *§?. pectini/era {Atrypa pectinifera
Sowerby), aus dem Zechstein, /§?. Boissyi^ (Sp. de Iloissyi Le-
v^ill^)," &c.. Op. cit., p. 832.

In the same year Eichwald placed A. tumida in Athyris and
S. concentrica in Spirigera*

In 1860 he also introduced the same classification in his great
work on the Paleontology of Bussia. The Bussian species are
A. tumida, didyma,»ungula, cassidea, S. concentrica and ambigua.'f

In my studies of the Canadian Brachiopoda I had no occasion
to describe any species of this ffroup until 1859, when I commen-
ced a series of papers on the Devonian Fossils of Canada
West At that time I had not fully investigated the subject, but
understood from a paper published by Mr. Davidson in the
" Geologist" (vol. 1, 456), and also from Woodward's "Manual
of the MoUusca" (p, 223), that A. tumida and S. concentrica were
thought to be inseparable.^ Not feeling perfectly satisfied that
this was the correct classification, I prefhced my descriptions with
the following remarks : —

Genus Athyris, — McCoy.

** There is much difference of opinion as to tbe propriety of retaining
tbis generic name. It implies that the shells have no foramen in tbe
ventral valve, and jet many are placed in the genus which have the beak
distinctly perforated. Some paleontologists are, therefore, in favor of
using D'Orbigny's appellation Spirigera instead of Athyris, 'Nearly all of
tbe Silurian species, and some of those from the Devonian rocks, have thd
beak so strongly incurved, that no foramen can be seen. For such, at

* Beitrag zur geogrsDhiachen VerbreituDg der fossilen Thiere Rusalands. BoIL
Soc. imp. Nat Moeoou, f ol. zzix, pp. 419, 422.

t Lelhan Houiea, vol. ii, p. 781 {AihyrtM); p. 786 (Spirigera),
X lo this work Mr. Woodward separates Meritta (although with doubt) as a sab-
genus, and refers A, tumida to Athyrii,



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60 E. Billings on the Genus Aihyris.

least, the name Aihyris does not appear to be very inappropriate. Mr.
Davidson still retains it, not only for those which have the foramen con-
cealed, but also for those with it open. It appears probable that the
genus will sooner or later be sub-divided, and in that case Aihyris might
be retained for the species with closely incurved beak, and Spirigera for
some of the others. I shall give some account of the generic characters
of this group of shells in another article. The following species are
placed in the genus provisionally." — Canadian Journal, p2], vol. v, p.
273, May, 1860.

In that paper I described two species with closed beaks, A.
clara and A, Maia, which, no doubt, belong to the eenus. The
others with perforated beaks, I marked doubtful, thus : — A. (?)
seUula (Hall) ; A. (?) Clusiay n. sp. ; A. (?) unisulcaia (Conrad) ;
A. (?) rosirata (Hall) ; A. (?) ChUk, n. sp.*

I think it the same as the species called Msrisiella Doris by Prof. Hall
(13th Reff. Rep., p. 84, 1860). I doubt that any of the others belong to
either Awyris or Spirigera,

Afterward Prof. Hall (18th Eeg. Rep., p. 74) nroposed to estab-
lish a new genus MerisieUa, precisely identical with AihyriSy as
re-defined by McCoy, in 1852. His diagnosis reads thus : —

" Shells variable in form, oval, ovoid, orbicular or transverse. Valves
unequally convex, with or without a median fold and sinus; beak of the
ventral valve apparently imperforate, incurved over the beak of the small*
er valve ; area none ; valves articulating by teeth 'and sockets. Surface
smooth, or with fine concentric lines of growth and fine obsolete radia-
ting stris, which are usually more conspicuous in the exfoliated shell.
The interior of the dorsal valve is marked by the presence of the longi-
tudinal septum, and the upper part of the ventral valve by a deep sub-
triangular muscular impression which unites with the rostral cavity."

Now I hold that instead of proposing a new genus, he should
have retained the original name Aihyris; because his proposition
amounts to a subdivision of the group, and according to tne laws
of nomenclature he should have applied the old name to that
portion for which it is most appropriate, as had been done six
years before by Davidson. As soon as this new arrangement
was published, I re-investigated the subject; and perceiving that
it amounted to nothing more than a restoration of Davidson's

* I now think that A, clara i» the lame as Prof. Hall's MerUttUa tiattita, bat
Am not quite 8ur« tbat it is Ooarad'a species. A. (f) tdtula was afterward found
to belong to a new genus described by me under the name of Charionella. (Dpi
/dt, vol vi, p. US, March, 1861). It is not Atrypa acitula HaU, a point on which I
was not certain at the time, as will be seen by the description, which reads thus :—



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