George W. (George Washington) Tryon.

Manual of conchology; structural and systematic. With illustrations of the species (Volume 15) online

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needle-like hairs, rising now in tufts, now in irregular crystals, be
examined under the microscope, it would be difficult to find any
shell of such surpassing beauty. Only one perfect specimen was
found, but fresh valves belonging to several other individuals were
detected among the Spondylus washings. The valves in the same
shell greatly differ in color as in L. albolineatus. The posterior
valve is peculiarly exquisite in its form, color and sculpture. There
is considerable variation in the size of the tubercles and in the stria-
tion of the j ugum. ( Cpr.)

A. RHODEUS Pilsbry, n. sp. PI. 12, figs. 48, 49, 50, 51.

Oblong, the exposed portion of the valves about one-third the
entire width of the animal. Valves depressed, obtusely carinated,
brown, the eroded apices roseate.

The intermediate valves appear almost separated by the encroach-
ment of the girdle at the sutures; a heart-shaped or subtriangular
area remaining exposed. Dorsal band sharply defined and strongly
differentiated from the side areas, very narroiv, shining, having slight
growth-lines but no longitudinal strice. Latero-pleural or side areas
sculptured with rounded-oval concave-topped elevations arranged in
rows subparallel to the ridge, becoming radial and then irregular at


the sides. Posterior valve having the tecjmentum drop-shaped, nar-
rower in front, longer than wide; mucro at the posterior fourth.

Interior deep rose red, paler at the edges of each valve. Slits
rather deep and narrow, arranged as usual. Insertion plates of all
valves very distinctly rugose outside. Posterior valve normally slit;
not noticeably bilobed behind.

Girdle wide and fleshy in alcoholic specimens, having 18 con-
spicuous tufts.

Gills extending forward two-thirds the length of the foot.

Length 28, breadth 15 mill, (alcoholic specimen.)

Panama (McNeill Expedition.)

Described from an alcoholic specimen which has lost the cuticle
and hairs from its girdle leaving a smooth whitish surface pitted at
the sutures. The salient specific characters are (1) that the girdle
encroaches much at the sutures ; (2) that the substance of the valves
is rose-red ; and (3) that the sculpture is altogether peculiar. The
insertion-plates are uncommonly rugose outside. It differs from A.
hemphilli in the normal 2-slit posterior insertion-plate.

The pustules (pi. 12, fig. 49 x 60) are mainly rounded or short
drop-shaped, and are arranged in regular rows. They become some-
what more spaced and less regularly arranged at the sides, and the
valve illustrated has suffered erosion toward the beak. The individ-
ual pustules (fig. 49) are seen to be decidedly concave. The dorsal
area is narrow, elevated and smooth except for growth stride. The
insertion and sutural plates are distinctly and sharply striated.

A. HIRUDINIFORMIS Sowerby. PI. 2, figs. 56, 49.

Shell oblong, flattened, blackish-green. Valves rounded, granu-
lose ; central areas elongated, acuminate behind, smoothish. Girdle
very densely pilose, velvety, with 9 concolored bunches of hairs.

Length 25, breadth 14 mill. (Sowb.*)

Ancon, Lobos Island and Payta, Peru ; Chatham Island, Galap-
agos, under stones at low water.

Chiton hirudiniformis SOWB., P. Z. S. 1832, p. 59 ; Conch. Illustr.
f. 23, 142. REEVE, Conch. Icon., t. 10, f. 54.

A. STYGMA Rochebrune. PL 8, figs. 31, 32.

Shell ovate-elliptical, the shell quite wide, pale brown, each valve
regularly encircled with a wide concentric black band. Anterior
valve rounded ; posterior small, somewhat swollen ; intermediate
valves having the central and lateral areas most minutely punctic-


ulate, surrounded by a wide smooth band. Girdle tawny, ornamented
with gleaming white, glassy tufts.

Length 35, breadth 20 mill. (Eochebr.')

Strait of Magellan.

Acanthochiton stygma ROCHEBR., Miss. Sci. du Cap Horn, vi,
Zool., p. 134, t. 9, f. 2a, 2b (1889). Not C. stigma Costa.

It is evident that but little dependence can be placed on the
figures of this species.

A. BISULCATUS Pilsbry, n. sp. PI. 4, figs. 86, 87.

Oblong, elevated, carinated, the side-slopes flat and straight.
Buff, maculated with olive-green and dark green, or greenish with
dark green and blackish mottling.

Anterior valve having the evenly granulated tegmentum extend-
ing two-thirds of the distance to the edge of the teeth. Intermediate
valves (fig. 87) having a very broadly heart-shaped tegmentum ;
the dorsal area triangular, convexly raised, longitudinally striated.
Latero-pleural areas distinctly concave or hollowed out on each side of
the dorsal area; covered with rather thickly distributed, drop-
shaped flat or concave pustules (fig. 86) averaging about one-sixth
of a mill. long. Posterior valve having the tegmentum symmetrically
oval, the long axis of the oval transverse to that of the animal ;
mucro prominent, subcentral.

Interior bluish. Insertion-plates and teeth normal. Tract behind
the sinus spongy. Posterior valve having one slit on each side, but
hardly a perceptible sinus behind.

Girdle rather wide, densely clothed with whitish spinelets, and
having 9 tufts on each side.

Length about 22, breadth about 9 mill.; divergence 100-110.

Habitat unknown.

Although the habitat of this species is unknown to me, I antici-
pate no difficulty in its recognition. The shallow but distinct sulcus
on each side of the dorsal area is a diagnostic feature, but unfortu-
nately is not shown in the figure.

(5) Undetermined, and unrecognizable S2)ecies of Acanthochite*.

ACANTHOCHITES TRISTIS Rochebr. Shell broad, ovate, sooty,
carinated, subumbonate. The anterior valve rounded, posterior
swollen ; intermediate valves having the central areas transversely
roughened ; lateral areas with sparse, wide tubercles. Girdle wide,


sooty, with 9 whitish tufts. Length 25, width 14 mill. (Rochebr.,
in Bull. Soc. Philom. Paris, 1881-'82, p. 194.)

New Holland (Dussumier; Paris Mus.)

ACANTHOCHITES TURGIDUS Rochebr. Shell small, ovate-oblong,
pale buff. Anterior valve elongated, posterior rounded, nearly con-
cealed ; intermediate valves rounded, covered throughout with
swollen tubercles. Girdle gray, with 9 blue tufts. Length 10,
breadth 6 mill. (Rochebr. in Bull. Soc. Philom. 1881-'82, p. 194).
New Holland (Peron & Lesueur ; Paris Mus.)

ACANTHOCHITES JUCUNDUS Rochebr. Shell ovate-elongate, buff,
with emerald-green lines and spots. Central areas of intermediate
valves smooth ; lateral areas sculptured with radiating beaded lines.
Girdle wide, roseate, with 9 green tufts. Length 24, breadth 13
mill. (Rochebr. in Bull. Soc. Philom. 1881-'82, p. 194.)

New Holland (Belligny) ; Cook's Straits (Filhol). Not common ;
Paris Mus.

ACANTHOCHITES STERCORARIUS Rochebrune. Shell elliptical
rather flat, dull olivaceous; anterior valve rounded; posterior
small, swollen ; intermediate valves with the central area rugose,
lateral areas covered with wide, concentric imbricating sulci. Girdle
wide, thick, shistaceous, with 9 greenish bunches. Length 22,
breadth 13 mill. (Rochebrune, in Bull. Soc. Philomath, de Paris,
1883-'84, p. 32, 1884.)

Cape Roxo, west coast of Africa (Paris Mus.)

ACANTHOCHITES BELLIGNYI Rochebrune. Shell elongated ;
ashen, marbled with white and tawny. Anterior valve rounded
elliptical, posterior very minute; intermediate valves having the
central areas smooth, lateral areas concentrically scaly, scales
spatuliform. Marginal ligament rather wide, brown, with 9 blue
bunches. Length 15, breadth 8 mill. (Rochebr., in Bull. Soc.
Philom. Paris, 1883-'84, p. 37, 1884.)

New Caledonia (Paris Mus.)

ACANTHOCHITES DAKARIENSIS Rochebr. Shell elongated, buff,
with a conspicuous black spot ; anterior valve broad, rounded ; pos-
terior valve nearly covered, semi-lunate; intermediate valves
rounded, scale-shaped, beaked behind, granulose, the granules sub-
imbricated ; anterior area of the valves wide, longitudinally sulcate,
the sulci chain-like. Marginal ligament wide, pilose, blackish, beset


very densely with whitish hairs; bunches 9, glassy, intense green.
Length 35, breadth 12 mill. (Rochebr. in Bull. Sue. Philomath.
1880-'81, p. 116 ; Journ. de Conchyl. 1881, p. 44.)

Rocks of Dakar, west Africa (Paris Mus.)

ACANTHOCHITES JOALLESI Eochebr. Shell elongated, thick,
almost always covered with a calcareous incrustation ; anterior valve
semilunar ; posterior valve rounded, small ; intermediate valves
rounded in front, semi-lunate behind ; lightly scaly at the base
only. Marginal ligament very broad, olivaceous, having sparse,
whitish long hairs ; 9 wide greenish bunches. Length 24, breadth
14 mill. (Eochebr. in Bull. Soc. Philom. Paris, 1880-'81, p. 117 ;
Journ. de Conchyl. 1881, p. 45.)

Coast of Joalles ; rocks of Eufisque, West Africa (Mus. Paris.)

CHITON ECHINOTUS Blainv. (Diet. Sc. Nat. xxxvi, p. 552). A
species said to be from the Ocean coast (of France), figured in the
Encyclop. Meth., pi. 163, f. 14, 15, copied from Chemnitz, vol. x,
pi. 173, f. 1688. It is practically unidentifiable, but the figures were
in all probability drawn from Acanthochites discrepans.

CHITON POLYCHETUS Blainville. Body very small, oval ; girdle
provided with 9 closely placed pairs of large tufts, the spicules equal,
silvery. Shell very small ; the disc of the intermediate valves quite
large and having 5 nearly equal sides; plates of insertion moderate,
unifissate far backward; that of the posterior valve with 3 nearly
equal lobes. Color greenish-brown. (Blainv., Diet. Sc. Nat. xxxvi,
p. 553.)

Seas of New Holland.

CHITON ROSEUS Blaiuville. Body oval, a little elongated, sub-
vermiform ; girdle much extended, covered with a very great
quantity of crowded hairs, concealing the very small tufts of bristles.
Bodies of the intermediate valves subtriangular, the anterior
summits truncated ; covered with flat tubercles at the sides. Color
of the shell rose; the rest of a gray black. (Blainv., Diet. Sc. Nat.
xxxvi, p. 553.)

New Holland.

Probably a species of Notoplax.

CHITON SUEURII Blainv. Body small, oval, Oniscus-Yike. Girdle
with 9 pairs of tufts of quite small bristles. Intermediate valves
having the body trapezoidal, with a brush-like group of stride in the


middle, the plates of insertion of medium size. General color gray-
ish. (Blainv., Diet. Sc. Nat. xxxvi, p. 553.)

Port of King George.

CHITON SCABER Blainv. Body oval, elongated, a little vermiform
having the girdle very thick and very wide, covered with quite fine
hairs and small tufts. Shell small, occupying only a third of the
back, formed of 8 thin, fragile valves, the intermediate ones larger
than the terminal, exposed portion triangular and very small in
comparison with the plates of insertion, which are wing shaped.
Insertion-plate of the anterior valve especially large, 6-lobed ; that
of the posterior valve patelliform, with 4 lobes. General color of
the shell whitish gray. (Blainv., Diet. Sc. Nat. xxxvi, p. 553.)

Seas of New Holland.

Section Notoplax H. Adams.

Notoplax AD., P. Z. S. 1861, p. 385 (type N. speciosa H. Ad.).
Macandrellus CPR. MS. in DALL, Proc. U. S. Nat. Mus. 1381, pp.
284, 288 (type M. plumeus Cpr.)

Acanthochites in which the posterior valve has the insertion-plate
grooved outside and denticulate at the edge, between the usual two
latero-posterior slits. Tegmentum reduced in size by the encroach-
ment of the girdle at the sutures, the valves nearly or wholly
separated there. Anterior valve not distinctly ribbed radially, or
lobed around the edge.

A rather weakly characterized section, probably artificial, but
decidedly convenient at present as a means of splitting the large
mass of Acanthochites. It is intermediate between typical Acantho-
chites and Oryptoconchus in characters. The girdle has the tufts
rather smaller than in the more typical Acanthochites, and the
spicular covering of the whole surface varies from nearly obsolete to
a dense clothing.

The true nature of the girdle in Notoplax was not known to Dr.
Dall when he wrote the notes upon the group in Bull. Mus. Comp.
Zool. xviii, p. 417. In the typical species, N. speciosa, it exhibits
all the characters of the girdle of Acanthochites. There seems to be
no character of more than specific value separating Notoplax and
Macandrellus. As to Stectoplax, which Dall (I. c.) thinks may prove
to equal Notoplax, it is absolutely nothing but a genuine Acantho-


The type of Macandrellus is not M. costatus Ad. & Ang., as stated
by Dall in Proc. U. S. Nat. Mus. 1878, p. 299, but if. plumeus Cpr.,
teste Dall, 1. c. 1881, p. 288. The first use of the name, being
unaccompanied by a diagnosis, will fall. At the time Carpenter
established the group for M. plumeus, he had never seen the species

A. SPECIOSUS H. Adams. PI. 1, figs. 23, 24, 25, 26.

Shell elongated ; valves acutely heart-shaped, olivaceous maculated
with brown ; each valve with a wide, smooth dorsal ridge, the side
areas coarsely granulose, the lateral area indicated by a raised line.
Girdle brown, spinulose ; pores moderate sized, encircled by con-
spicuous spicula.

Length 72, breadth 24 mill. (H. Ad.)

Tasmania (Mus. Cuming) ; flinders Island (Jos. Milligan.)

Cryptoplax (Notoplax) speciosa H. AD., P. Z. S. 1861, p. 385.

This species resembles A. exquisitus Pils. in the narrowness of the
exposed portion of the valves, but in typical specimens of that form
the tegrnentum is decidedly narrower. In A. hemphilli Pils. from
Florida, which is a Notoplax in its apparently separated valves and
denticulate tail-plate, the speciosus differs in' the longer, narrower
tegmenturn, etc.

The figures of my plate were drawn by Mr. E. A. Smith from the
types. Carpenter gives the following useful notes on the specimens
in the British Museum : The lateral areas are distinctly marked
off by larger granules along a raised diagonal line. The mucro of
the posterior valve is raised, at an angle of about 160, and situated
at the posterior third of the tegmentum. The jugular areas are
both smooth and raised ; the scales of the sides are also smooth flat
and raised. The girdle is entirely covered by a dense mass looking
spongy, but consisting of spicules of moderate length and extremely
crowded. There are conspicuous pores but the hairs in them are
not longer than the rest, and therefore it is difficult to distinguish
them. The sinus is very narrow and deep. Slits all very short.
The anterior valve has grooves with raised edges extending from
eaves to the slits. Posterior valve having side slits, situated as in
Acanthochites, but the posterior plate is pretty regularly grooved
radially, so as to crenate the margin, almost amounting to little nicks
from slit to slit.


A. FORMOSUS Keeve. PL 1, figs. 12, 13 (enlarged.)

Shell oblong, rather narrow; valves very finely longitudinally
striated at the summit, granulated at the sides. Bright scarlet.
Ligament horny, thickly beset with shining white spicula at the side
of each valve. Length ?, breadth T\ inch. (Reeve.)

Cape Rivers, N.- W. Celebes ; one specimen.

Chiton formosus REEVE, P. Z. S. 1847, p. 25 ; Conch. Icon., t. 26,
173. ADAMS & REEVE, Zool. 'Samarang,' t. 15, f. 8.

Carpenter believed his MS. species Macandrellus plumeus to be the
same as this, although he had not, I believe, compared the types.

His description is as follows :

A. plumeus Carpenter. Shell subelongate, subelevated, the dorsal
ridge acute, mucro submedian, hardly raised, the slope behind it
concave. Roseate at the sides, olivaceous in the middle. Exposed
part of the valves small. Posterior valve subrotund ; anterior valve
pectinated and 5-angled around the margin ; central valves strongly
angular, beaked ; sutures deeply encroaching on the side-areas.
Dorsal areas delicately and closely sublongitudinally lirulate ; lateral
areas distinctly defined, sunken ; central and lateral areas scaly in
radiating, somewhat plumose pattern.

Interior : posterior valve hardly sinuated behind, having a slit at
each side, the plate between them deeply grooved outside and sub-
dentate, shallowly slit at the edge. Anterior valve having 5 slits,
the teeth angular at the slits. Girdle leathery, smooth, sometimes
somewhat spongy, having minute hairlets, and small tufts of hairs
at the sutures. Length 21, breadth 11 mill. ; divergence 120.

Habitat unknown (Mus. Cuming, no. 108.)

Macandrellus plumeus CPU. MS. ; and in Dall, Proc. U. S. Nat.
Mus. 1881, p. 288 (no description.)

The irregular, rugose lobes of the tail plate, behind, almost
amount to teeth. The head valve is hexagonal. The sculpture
resembles the feathers of a bird. The lateral areas are distinct, but
sunken instead of raised. ( Cpr.)

A. ACUTIROSTRATUS Reeve. PI. 8, figs. 27, 28.

Shell elongated, elevated in the middle, somewhat compressed at

the sides ; valves obtusely keeled at the summit, smooth ; very closely

flatly grained on each side; umbones produced, sharply beaked;

lateral areas of the valves small, rather indistinct, concave. Whit-



ish, stained here and there along the summit with black. Ligament
horny, furnished at the side of each valve with a small crest of
spicula. (Rve.*)

Cape Rivers (Belcher.)

Chiton acutirostratus REEVE, Conch. Icon., t. 26, f. 137. July,
1847. Voy. Samarang, Moll., t. 15, f. 10.

An elongated species of somewhat compressed growth, remarkably
distinguished by the sharply beaked structure of the umbones ; the
flat-grained sculpture of the valves approaches that of C. hirudini-
formis, to which it offers a singular contrast of color. (Reeve.)

A. HEMPHILLI Pilsbry, n. sp. PL 13, figs. 65, 66, 67.

Elongated, the valves somewhat exceeding one-third the total
width in dried specimens. Valves rather elevated, carinated ; red,
more or less maculated with white. Girdle rust-brown.

The intermediate valves are not beaked, being somewhat produced
backward on each side of the apex ; tegmentum reduced to a heart-
shaped area by the encroachment of the girdle at the sutures, leaving
the valves in contact by only a small point at the ridge. The dorsal
band is very narrow, parallel sided, slightly elevated, and having a
few longitudinal strise. The latero-pleural or side areas are sculpt-
ured with fine flattened pustules, those on the posterior portion of
each valve being concave. Posterior valve elevated, the tegmentum
small, somewhat pear-shaped, narrow in front, longer than wide, mucro
at about the posterior third.

Interior light green at the sides, deep rose-red in the middle and at
the posterior margin of each valve. Sutural-plates light greenish,
the slits minute. Posterior valve not bilobed behind, having the usual
two slits, and between them a number (6-8) of smaller, irregular and
unequal slits or nicks ; posterior sinus obsolete.

Girdle wide, rusty-brown, sparsely clothed with short microscopic
hyaline spicules, having a fringe of longer spicules at the periphery,
and 18 rather small tufts of whitish bristles.

Length 24, breadth 11 mill. ; divergence about 115.

Key West, Florida (Henry Hemphill.)

This species is allied to A. rhodeus in the peculiarly narrow
dorsal band, the great encroachment of the girdle at the sutures,
etc. ; but it differs in the less developed side slits, the higher and
narrower tail valve and its peculiar multiple-slitting, and in other
features. It was collected by Mr. Hemphill at Key West. There


are other specimens in the collection of the Geological Survey of
Canada, without locality.

The pustules are rounded, flat-concave topped, crowded, and
arranged in distinct series. The dorsal area projects anteriorly
beyond the latero-pleural areas ; it is narrow, elevated and longitu-
dinally striated, the striae mostly rather indistinct and subgranulated.
The white and crimson pattern gives an appearance of great elegance
to the valves.

A. CARPENTERI Pilsbry, n. sp. PI. 1, figs. 14-22.

A series of drawings left by Dr. Carpenter, represent an unnamed
new species of Maeandrellus, of which he had prepared no descrip-
tion. It is so strongly marked, however, that the recognition of the
form will be easy. Its prominent features are : (1) the broad, ante-
riorly produced, slightly asperulate girdle with minute pore-tufts ;

(2) the slightly scalloped border of the anterior valve (tegmentum) ;

(3) the coarse scale-like granulation of the side areas ; and (4) the
distinct slitting of the posterior insertion-plate into even, vertical
teeth. Length 41, breadth 23 mill.

Port Elizabeth, S. Africa.

The figures of detached valves are double natural size. Compare
A. INVOLUTUS Carpenter, n. sp. PL 1, figs. 27-35.

An unpublished species, of which excellent figures by Emerton
were prepared for Carpenter. These are reproduced upon my plate,
and are sufficient for the recognition of the species, although the
sculpture is represented upon the head valve only. All the figures
are magnified two diameters. Carpenter gives only the following
notes : There are only six stumpy [branchial] leaflets on each side
of the tail ; vent inconspicuous ; foot slight and very thin. Head
very small, with copious " veil " and neck lappets, outside of which
there is a sort of hood around the head, extending backward to the
gills (fig. 33), without epidermis, like the foot ; outside of all is the
large girdle covered inside with granular epidermis."

Zanzibar (Mus. Comp. Zool.)

The figures were drawn from alcoholic specimens.

Section Cryptoconchus Blainville & Guilding, 1829.

Cryptoconchus (BLAINVILLE MS. in Brit. Mus. ; BURROW, Elem.
Conch., p. 190), GUILDING, Zool. Journ. v,p.2S (1829). GRAY, P.
Z. S. 1847, p. 66, 69, 169. Type C.porosus.


Valves entirely covered by the girdle except a linear area at the
ridge of each. Posterior valve having the insertion-plate with several
(5-7) slits, anterior valve 5-slit. Girdle leathery, naked, bearing a
series (18) of sutural tufts on tubercles, or pores, sometimes sub-
obsolete, along the sides of the valves. Gills extending along the
posterior half of the foot.

This subgenus cannot in fairness be dated from the time of its
pullication in Burrow's Elements, for in that work it is in no way
defined and is disowned as a valid genus. Burrows simply says that
Blainville has affixed the names Cryptoconchns porosus and C. larvce-
formis to two specimens in the British Museum. The latter belongs
of course to Chitonellus. In 1829, Guilding adopts Cryptoconchus
as a genus, and gives a generic diagnosis. Blainville himself ignores
the name in his publication on Chitons in 1825, believing it a
synonym of Chitonellus.

This group is much more closely allied to Acanthochites than to
Amiada ; its valves being exactly the form which would be pro-
duced by a little further covering of the side areas in a species like
A. (Notoplax) hemphilli. The backward prolongation of the sides
into posterior lobes is just as great in that species ; the main differ-
ence being that in Notoplax these posterior lobes are not covered by
the girdle. The structure of the tail valve is practically the same in
Notoplax, Loboplax and Cryptoconchus.

A. POROSUS Burrow. PI. 3, figs. 57, 58, 59, 60, 61, 62.

Shell elongated, all but a linear dorsal area of each valve covered
by the integument continued upward from the girdle, but in the
dried state showing through it the posterior outlines of the valves.
Color when dry dark reddish or blackish-brown.

The outer layer of each intermediate valve is reduced to a narrow
dorsal area, shaped like an exclamation point without the dot (') ;
upon each side of the apex, the posterior margin of each valve is pro-
duced backward in a rounded lobe, showing plainly through the con-
tracted outer skin. A more or less developed groove extends to the
lateral slits. Head and tail valves with minute circular exposed

Interior light blue-green. Anterior valve having 5, median
valves 1, posterior 5-7 slits.

Girdle reddish- or blackish-brown in the dried condition, naked,
smooth, leathery ; bearing a series of prominent tubercles each with a


bunches of short bristles, situated Dear the sutures upon the sides of
the valves, and four around the head valve.

Length 34, breadth 14 mill, (dried specimen.)

Length 38, breadth 20 mill. (. & .)

Dunedin to Auckland, New Zealand.

Chiton porosus BURROW, Elements of Conchology, p. 189, t. 28,
f. 1 (1815). Cryptoconchus porosus H. & A. AD., Gen. Rec. Moll,

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