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Calif. ! In British Columbia in eastern Kootenai Lake, Lake Siniak-
wateen, and Osoyoos Lake !

As pointed out by Binney, this is quite distinguishable from any
form of trtvolvts ; it differs from the true corpulentus, with which it
was long confounded, in its sparser and less regular axial sculpture,
larger and less campanulate aperture, and in the greater distance of the
carina from the axis. Its whorls increase more rapidly than in P.
traskii Lea, or even P. ammon Gould, 1 and its sculpture is markedly
coarser and less regular than in either of the two last cited. It is not
known north of British Columbia or east of the Rocky Mountains.





FIGS. 66, 67. Planorbis binneyi, showing animal and shell.

Planorbis (Pierosoma) trivolvis Say.

Planorbis trivolvis SAY, Nicholson's Encyc., isted., n (no pagination), pi. n,

fig. 2, 1817 ; Am. Conch., vi, pi. 54, fig. 2, 1834 (French Creek, Lake

Erie).
Planorbis macrostomus WHITEAVES, 1863 (abnormal) ; -f- P. lentus Gould, and

many other writers, but not of Say ; + P. tumens various California

writers.
Planorbis subcrenatus CARPENTER, P. Z. S., 1856, p. 220.

Range. The typical form belongs to the entire Atlantic drainage
of North America and the Mississippi Valley and northward to the
Etchimamish River.

English River, Keewatin ; Lake Winnipeg, Manitoba ; Cypress
Hills ! Assiniboia ; Prairie Lake, Red River of the North ! ; the
Saskatchewan River, Laggan, Egg Lake, Red Deer, McLeod, and
Olds, Alberta; Lake Isle Lacrosse, Athabaska; Great Slave Lake,
at Fort Resolution ! and the Mackenzie River at old Fort Simp-

1 These two species, judged by their types, which are before me, are suffi-
ciently distinct from any of those which have been confounded with them. In-
deed the true P. traskii from Kern Lake, Calif., is one of the most remarkable
species in our fauna. It was also found by me at Stockton, Calif., and seems to
have been unknown, autoptically, to Binney.



FAMILY LYMN^ID^-E



son! (N. Lat. 62). We have it from Moose Factory! the Slave
River 2 ^ miles below Peace River ! Lake Winnipeg ! the Grand
Rapids of the Saskatchewan River I and hundreds
of more southern localities.

The variety subcrenatus Carpenter (Oregon,
Nuttall) occurs in British Columbia west of the
Cascades ; being, according to J. K. Lord, replaced
east of them by P. binneyi. We have it from
the Puget Sound drainage ! Lake La Hoche !
and Sumas Lake, B. C. ! A distorted variety
(disjectus Cooper) is reported from Lake Tahoe,
Calif., at a height of 6,247 feet above the sea.

The young shell was described from Pueblo Val-

PIS tnvolvis.

ley, Oregon, by Tryon in 1865, as P. oregonen-

sis. In 1870 Cooper called the more common adult (but not senile)
form P. occidentalis^ and later confounded it with the Mexican P.
tumens Cpr., and gave it a range in California from Kern Lake,
Tulare Co., north to Puget Sound, and, in the coast drainage, to San
Francisco Bay. There is a doubt as to whether Planorbis hornii





FIG. 69. Planorbis trivolvis var. macrostomus Whiteaves.

Tryon (1865), from " Fort Simpson, British America," came from
Fort Simpson on the Mackenzie River, or Fort Simpson, British
Columbia ; but the figure looks more like the Pacific variety, of which
it is probably only a mutation. We have specimens from various
places in California, and Wallawalla, Wash., labelled P. hornii which
are merely a depauperate form of subcrenatus,

On the other hand, from the Dall River, a northern affluent of the
Yukon in Alaska, in N. Lat. 66, we have the typical form of trivolvis



90 LAND AND FRESH WATER MOLLUSKS

stretching westward with the Yukon drainage ! I have never seen any
specimens corresponding exactly to Tryon's figure of P. hornii, but
the variations I have seen of P. subcrenatus often approach it so
closely that I have little doubt of their identity. P. macrostomus
seems, from an examination of the types, to be a form of trivolvis
which has survived a year longer than usual, in a locality where it was
not stinted in lime, resulting in a remarkably fine shell with richly
colored aperture.

Planorbis (Planorbella) campanulatus Say.

Planorbis campanulatus SAY, Journ. Acad. Nat. Sci. Phila. , II, p. 166, Jan.,
1821 (Cayuga Lake, N. Y.). HALDEMAN, Mon. Limn., p. 9, pi. i,
figs. 7-1 1, 1844.

Planorbis bellus LEA, 1844 (immature shell) 4- P. complanatus Miller Christy,
1885.

Range. The type: New England to Tennessee, Florida and
northward ; Anticosti Island ! Lake Superior to the Saskatchewan ; L.
Winnipeg, Red River of the North, Nelson and English Rivers ;
Moose Factory ! Great Slave Lake, N. Lat. 62 ; Lake
of the Woods !

Variety rudentis : Knee Lake, Hayes River, Kee-
watin, N. Lat. 55 (E. A. Preble) !

This well known species is confined to the Atlantic,
Mackenzie, and Hudson Bay watersheds, and has not

been reported north of Great Slave Lake. So far
orbts campanu-
latus Say. as the specimens examined go to show, it is rather re-
markably uniform in its characters, the number of
whorls remaining always about the same, though the actual size
varies with the food supply and healthfulness of the environment.

A form which may prove distinct, or a variety of this species, was
collected by Mr. Preble at Knee Lake. The comparative measure-
ments are :

Whorls. Major Diam. Minor Diam. Axis.

Type. 4.75 15.0 mm. n mm. 6.5mm.

Variety. 5.25 17.5 14 6.0

Very similar specimens were obtained from Anticosti Island and
from Marl Lake, Michigan, in which the coil is even more irregularly
wound, a condition I take to be pathological. The most noticeable
difference, after the axially shorter whorls and larger size, is in the
umbilicus, which in the variety is, as it were, reamed out, exhibiting
three and a half whorls ; while in the more compact type the umbilicus
when examined with a lens shows only two and a half whorls, which




FAMILY LYMN^EID^E 9!

diminish in size much more rapidly than in the variety. The campan-
ulate aperture is about the same size in both forms, but seems larger
in the type because the rest of the shell is so much more tightly
wound. The suture on the apical side seems deeper and wider than
in the type. Nine specimens of the variety were obtained, and I sug-
gest for it the name rudentis, from the similarity of the whorls to a
coiled hawser.

Planorbis (Menetus) exacuous Say.

Planorbis exacuous SAY, Journ. Acad. Nat. Sci. Phila., II, p. 1 68, Jan., 1821
(Lake Champlain) ; Long's Exp. Rep., II, p. 261, 1824.

Planorbis exacittus GOULD, Inv. Mass., p. 208, fig. 137, 1841. HALDEMAN,
Mon. Limn., p. 21, pi. iv, figs. 1-3, 1844.

Paludina hyalina LEA, 1839 (scalariform monstrosity).

Range. Northern United States, east of the Rockies; Canada,
etc., south to New Mexico.

Lake Superior to Lake Winnipeg ! Manitoba generally ; Moose
Factory, Hudson Bay ! Left bank of the Yukon below Fort Yukon,
Alaska, in Pleistocene marl (A. J. Collier) !

Variety megas Dall, nov. : Birtle, Manitoba (R. M. Christy).

This species has a number of varieties both in size and form. The
typical shell is of a pale brownish horn color, with a somewhat glisten-
ing surface, rather rudely striated by the incremental lines, and with
faint, almost microscopic, revolving striae. The form is lenticular,
coming to an acute angle at the periphery. In 1863 I found in the
vicinity of Marquette, Michigan, an unusually depressed brownish
variety in which the peripheral keel was delicately serrate. In the
northwestern part of its range the tendency is for the species to become
whitish and of a larger size than the average New York or New
England specimens. This reaches its maximum in specimens col-
lected in Manitoba by Mr. R. Miller Christy, for which I propose the
varietal name megas. The comparative measurements are as follows :

Whorls. Max. Diam. Min. Diam. Axis.

Type. 3.33 4.7 mm. 3.7 mm. i.o mm.

Variety. 3.75 7.8 6.0 2.0

The variety is of a slightly milky translucency ; on the base the
whorl is more or less impressed within the peripheral keel and the
spiral striation is much more marked than in the typical form.

Binney has united with this species Planorbis lens Lea, 1839 (not
Brongniart, 1810) = P. lenticularis Lea, 1844 ( not Schlotheim,
1818) = P. brongniartiana Lea, 1842 ; but an examination of Lea's



92 LAND AND FRESH WATER MOLLUSKS

cotypes, now in the National Museum, makes it evident that Dr.
Gould was right in referring this form to P. dilatatus Gould, 1841 (not
Pfeiffer, 1841 *), or dilatus Haldeman, 1844. To this latter form, in
my opinion, should be united, as local races, P. buchanensis Lea,
1844, and P. alabamensis Pilsbry. The young of P. exacuous Say
frequently approach dilatatus, but the latter can usually be distin-
guished by its axial height being greater, its columella more vertical,
and the substance of the shell, especially in southern specimens, more
thick and solid. The aperture of the adult dilatatus is usually dis-
tinctly thickened by a deposit of callus, but in exacuous I have never
observed more than a very thin wash of shelly matter around the open-
ing. I have spelled the name of this species as Say did in two sepa-
rate works ; as he gave no derivation it seems to me we have no right
to correct his spelling on purely theoretical grounds.

Planorbis (Menetus) opercularis Gould.

Planorbis opercularis GOULD, Proc. Boston Soc. N. Hist., n, p. 212, 1847 ;
Moll. U. S. Expl. Exp., p. 113, Atlas, figs. 132, 132, a-b, 1852 (Sacra-
mento River, Calif.).

Planorbis planulatus COOPER, Rep. Nat. Hist. Wash. Terr., p. 378, 1859 ;
Pacific R. R. Rep., xn, p. 378. BINNEY, Land and Fw. Shells N. Am.,
pt. II, p. 126, fig. 209, 1865.

Planorbis centervillensis TRYON, Mon. Fr. Univ. Moll. U.S.,

p. 57, Planorbis, pi. vn, figs. 7-9, 1872.
Planorbis opercularis var. oregonensis VANATTA, Nautilus,
IX, p. 53, Sept., 1895 ; not P. oregonensis Tryon,
1865.
Planorbis callioglyptus VANATTA, Nautilus, ix, p. 54, 1895.

Range. San Francisco and northward, west of the
Sierra Nevada.

Type form : California ! Oregon ! Washington
near Seattle !

Variety planulatus W. Cooper : Whidbey Island,
Puget Sound ! Shawnigan Lake, Vancouver Island !
Seattle, Wash. ! Freeport, Wash. ! Victoria, B. C. !
orbisopercularis C bell > s Creek B> C . j Pend er Island, B. C. !
Gould (typical). ,.,, . _,

Atka Island, Aleutians, Alaska, near Korovin Bay !

Variety centervillensis Tryon : Alameda, Calif. ! Noyo River,
Calif. ! San Leandro, Calif. ! Oregon ; Unalaska Island, Alaska !
Variety oregonensis Vanatta : Salem and Portland, Oregon !

1 1 learn through Prof, von Martens that Pfeiffer's species was published in
the double part v-vi, of the Archiv fur Naturgeschichte, either in the last part
of 1841 or the early portion of 1842, so that Gould's priority is certain.




FAMILY LYMN^EID^E



93




This species is the analogue of P. exacuous Say on the Pacific
Coast. The typical form from the Sacramento River and the vicinity
of San Francisco Bay is quite lenticular, with the periphery marked
by a (frequently marginated) keel. The shell itself is pale yellow or
white under a rather strong periostracum, which is
almost invariably more or less discolored by deposits
of a brown or black color. The sculpture is like that
of exacuous, the spiral sculpture being faint and FIG. 72. Plan-
sometimes absent in southern specimens, and tending orbisopercularis

to be emphasized in northern ones. As a rule the , ' *

Cooper,
margin of the aperture is not thickened except in

young specimens which have been overtaken by drought or winter
before maturity. The keel is generally, but not always, present in
southern shells, but those from Oregon and northward show a tend-
ency to form a shell either without a noticeable keel, or with the keel
forming a margin to a plane upper surface, rather than a median
carina. When compared with Cooper's types in the National Museum
Mr. Vanatta's P. callioglyptus is seen to be identical. The variety ore-
gonensis retains the typical form but has stronger spiral sculpture. I
regard P. centervillensis of Tryon as a P. -planulatus with the keel
obsolete. What appear to be intergradational forms are numerous in
the large series of the National Museum ; though it would seem incred-
ible to any one possessing only the extremes that they can belong to
the same species.

Planorbis (Gyraulus) hirsutus Gould.

? Planorbis albus MULLER, Verm. Terr, et Fluv., n, p. 164, 1774.

Planorbis hirsutus GOULD, Am. Journ. Sci., xxxvni, p. 196, 1840; Inv.

Mass., p. 206, pi. xi, fig. 135, 1841.
Planorbis borealis (LOVEN) WESTERLUND, Mai. Bl., xxii, p. 77, 1875.

Range. Washington, D. C. ! northward, east of
the Mississippi. Lake Superior ! Lake of the Woods !
Lake Winnipeg and the Saskatchewan River ! Great

Slave Lake !
FIG. 73. Plan-
orbis hirsutus Var. borealis Westerlund : Port Clarence, Alaska.

Gould. \. Northern Sweden.

This species appears to be common only in New
England, if one may trust reports, and it is remarkable how few
records there are of it in the literature of American fresh water shells.
The shell is variable in form ; from having, in what I have re-
garded as the type, well rounded nearly cylindrical whorls, it varies to
a form more or less depressed and carinate and with an oblique aper-




94 LAND AND FRESH WATER MOLLUSKS

ture, which, when it has lost its hispid periostracum, can hardly be
distinguished from the shell which is usually called deflectus of Say.
This latter form, which, when in perfect condition, is fully as hairy
as the typical hirsutus, is apparently identical with the shell
which European writers catalogue under the name draparnaudt
or drafarnaldi of Sheppard. In its best state this has a peripheral
fringe of longer hairs than those elsewhere on the surface, beneath
which is usually, but not always, a faint peripheral keel like that of
P. deflectus Say, which is distinguishable, so far as the shell is con-
cerned, only by its less profuse and hairy periostracum. I should not
be at all surprised if the two were eventually shown to be extremes of
one specific form, especially as I have been unable to find specimens of
typical deflectus which do not somewhere exhibit traces of spiral stri-
ation like that of P. hirsutus. The identity of our American species
with the so-called P. albus Miiller, of Europe, I do not doubt, but
whether the name albus is the proper one to use for the latter is open
to question, and on the present occasion I prefer to vise a name about
whose application no doubt can exist. The differences which have
been reported to exist between the New England and the European
shell are due to the comparison being made between discrepant varie-
ties. If a series including all varieties from many different localities
in Europe, be compared with a similar American series, parallels for
each variation will be found.

Planorbis borealis (Loven MS.) Westerlund, after specimens fur-
nished by Westerlund, is merely a somewhat delicately sculptured
mutation of this species.

Planorbis (Gyraulus) deflectus Say.

Planorbis deflectus SAY, Long's Exp. Rep., n, p. 261, pi. xv, fig. 8, 1824.
HALDEMAN, Mon. Limn., p. 25, pi. iv, figs. 4-7, 1844
(N. W. Territory).

Planorbis virens ADAMS, 1840; young shell.

Planorbis obliquus DE KAY, 1843.

Range. In America the same as that of P. hir-
FIG. 74. Plan-
,. , j, . sutus.
orbts deflectus

Sa y ? 2 Ottawa, Canada ! Lake of the Woods ! Great Slave

Lake ! Dall River, Alaska, Lat. 66 N. ! Popof Island,
Shumagins, Alaska (Kincaid) !

Doubtfully distinct from the preceding species. It differs chiefly
from the variety draparnaudi by the feebleness or absence of the
hispidity of the periostracum. The deflection of the aperture and the
consequent form of the mouth of the shell are inconstant characters,




FAMILY LYMN^EID^E



95



although they have been called ' characteristic ' by the very authors
whose evidence shows the inconstancy.

Planorbis (Torquis) parvus Say.

Planorbis parvus SAY, Nicholson's Enc., 1st ed., n (no pagination), pi. i, fig.

5, 1817. HALDEMAN, Mon. Limn., p. 27, pi. iv, figs. 19-23, 1844

(Delaware R.) BINNEY, Land and Fw. Sh. N. Am., II, p. 133, figs. 222-

223 (not 224), 1865.

Planorbis concavus ANTHONY, MS., various catalogues.
Planorbis elevatus C. B. ADAMS, Bost. Journ. N. Hist., in, p. 327, pi. in, fig.

1 6, 1840 ; young shell (S. Boston).
Planorbis billingsi LEA, 1866, from types (Ottawa, Canada).

Range. In America, the whole of eastern North America from
Florida to N. Lat. 67, and the Yukon drainage system.

Ottawa, Canada ! northward and westward to Lake Winnipeg ! the
Saskatchewan River ! Alberta at Laggan, Olds and McLeod ; Mani-
toba at Brandon and Birtle ! Methy Lake ; Moose Factory ! Fort
Simpson, Mackenzie River ! Lake Bennett, Yukon Territory ! Left
bank of the Yukon below Fort Yukon, Alaska !

The most striking characteristic of this widespread species is its
'reamed out' umbilicus. P. limophilus Westerlund, its nearest
European analogue, may be distinguished at once by its shallow and
flattish umbilicus. It rarely shows any trace of spiral sculpture and,
when clean, is brightly polished. In the last whorl of
the adult the portion above the periphery is usually
somewhat flattened or obliquely depressed.

Planorbis (Torquis) vermicularis Gould.

Planorbis vermicularis GOULD, Proc. Boston Soc. N. Hist.,
II, p. 212, 1847 ; Moll. U. S. Expl. Exp., p. 112, pi.,
figs. 131, a-b, 1852 (Oregon).

Range. Northern California ! Oregon ! and Van-
couver Island, British Columbia !

On comparison, the type of P. vermicularis is seen
to have vertically deeper whorls than a specimen of P.
parvus of the same number and diameter. The aper-
ture is more expanded, and much larger, as one
would expect from the greater lumen of the whorl.
Specimens from middle and southern California have
a different aspect and may prove on more careful study to belong to P.
parvus. They certainly do not agree with the Oregon shell, which,
however, I have seen from Noyo, California.




FlG. 75. Plan-
orbis vermicu-
laris Gld. (mag-
nified).



96 LAND AND FRESH WATER MOLLUSKS

Planorbis (Torquis) nathorsti Westerlund.

Planorbis nathorsti WESTERLUND, Vega Expd., iv, p. 168, 1887. POSSELT,
Consp. Fauna Gronl. Moll., p. 162, 1898.

Aulatsivik, West Greenland (Sofia Expedition) ; Labrador (Storer).

This species is said to approach P. arcticus, but has four and a
half turns in a diameter of 3.5 mm., while the latter turns only three
and a half times in 5.0 mm. P. nathorsti has spiral as well as trans-
verse striation. It has not been figured.

Some specimens in the National Museum collected in Labrador ex-
hibit about four turns in 3.5 mm. diameter, according to my calcula-
tion, but so much personal equation enters into the estimation of the
extent of the first whorl that I am inclined to think they belong to
Westerlund's species, in which case it is intermediate between par-vus
and arcticus, but without the excavated umbilicus of the former.

Planorbis (Torquis) arcticus Moller.

Planorbis arcticus (BECK, MS.) MOLLER, Index Moll. Gronl., p. 5, 1842.
MORCH, Am. Journ. Conch., iv, p. 32, pi. iv, fig. 9, 1868. MORCH, in
Rink's Danish Greenland, p. 436, 1877.

Range. West Greenland! Fort Chimo, Ungava, Labrador!

Species with larger whorls, the last more expanded near the aper-
ture, and with the sides of the umbilicus not excavated as in P. parvus
Say.

Planorbis (Torquis) umbilicatellus Cockerell.

Planorbis umbilicatus TAYLOR, Journ. Conch., iv, p. 351, 1885 ; not of Miil-

ler, 1774. Manitoba.
Planorbis umbilicatellus COCKERELL, Conch. Exch., II, p. 68, Nov., 1887.

VANATTA, Nautilus, ix, No. 10, p. 117, 1896.

Range. From Mesilla, New Mexico! northward, through Col-
orado, Montana, Iowa, Minnesota, to Manitoba.

Rapid City, Birtle, Brandon ! in Manitoba ; McLeod, Red Deer,
Olds, Laggan, in Alberta.

Planorbis (Anniger) crista Linn6.

Nautilus crista LINNE, Syst. Nat., ed. x, p. 709, 1758.
Turbo nautileus LINNE, Syst. Nat., ed. xn, p. 1241, 1767.
Planorbis imbricatus MULLER, Hist. Verm. Terr., II, p. 165, 1774-
Planorbis cristatus DRAPARNAUD, Hist., p. 44, pi. n, figs. 1-3, 1805.
Planorbis nautileus GRAY, Turton's Man. Land and Fw. Shells, p. 236, pi.

vui, fig. 94, 1857.
Planorbis costatus DE TAR and BEECHER, leaflet of one page, Albany, Oct.

25, 1878.
Planorbis crista WOODWARD, Brit. Nonmarine Moll., in Journ. Conch., x, p.

355.



FAMILY LYMNyEID^E 97

Range. Europe, Algeria, in the Old World ; in America at Cari-
bou, Aroostook Co., Maine! Hamilton and Ottawa, Canada; Ann
Arbor, Michigan ! Red Deer in Alberta ; Manitoba.

This small and inconspicuous species will doubtless be found in
many other localities when thorough search is made.

Genus Segmentina Fleming.

Segmentina FLEMING (1817, Edin. Encycl., ed. vu, vol. xu, fide Turton
Manual, p. 116, 1831); Brit. An., p. 279, 1828. Type Nautilus lacustris
(Lightfoot) Montagu. HALDEMAN, Mon. Limn., iv, p. 14, 1842.
STEIN, Schnecken u. Musch. Berlins, p. 78, 1850. WESTERLUND,
Fauna Pal. Reg., v, p. 85, 1885. WOODWARD, List. Brit. Nonmarine
Moll., p. 355, 1903.

Hemithalamus LEACH (1819), Proofsheets, p. 137, fide Turton, Manual, p.
116, 1831. FITZINGER, Syst. Verz., p. no, 1833. ROSSMASSLER,
Icon., I, pt. n, p. 15, 1835. H. nitidus (MULLER) LEACH = P. lineatus
Jeffreys.

Segmentaria SWAINSON, Malac., p. 337, 1840 ; lapsus pro Segmentina Fleming.

Hippeutis (sp.) AGASSIZ in Charpentier, Fauna Helvetica, p. 22, 1837.
HARTMANN, Syst. Uebers, tab., 1840.

Dentatus GRAY, P. Z. S., 1847, p. 181, not of Beck, 1837, P. armatus Gray ;
? = P. artnigerus Say -f- P> armiger Beck.

> Planorbula HALDEMAN, Mon. Limn., iv, p. 14, 1842, P. armigerus Say.

Discus HALDEMAN, Mon. Limn., I, p. 4 of cover, July, 1840 (P. armigerus
Say), not of Fitzinger, 1883.

This genus was founded by Fleming on the Planorbis nitidus of
Miiller, of which lacustris Lightfoot, is a synonym. I have not been
able to verify the reference to the Edinburgh Encyclopedia. Leach's
name was circulated in proof sheets, but not actually published or cited
by other authors until after Fleming's description appeared. Beck called
a group of Planorbes * Dentati ' but applied no name to the group,
and the transformation by Gray to ' Dentatus^ as if it had been in-
tended for a generic or subgeneric name, seems quite unwarranted.

The genus may be divided into three groups as follows :
Subgenus Segmentina s. s. Base flattened, coil close, margin of the
aperture simple, sharp ; lamellae ridgelike, several sets persistent in
the adult. Type P. nitidus Miiller. Palearctic region.
Subgenus Planorbula Haldeman. Whorls rounded, coil loose, mar-
gin of the aperture simple, sharp, slightly expanded ; lamellae denti-
form, only one set persistent in the adult. Type, P. armigerus
Say. Nearctic region.

Haldemanina Dall, n. sect., whorls carinate above and below, margin
of aperture thickened and reflected ; lamellae complex, dentiform
and ridgelike, one series persistent in the adult. Type, Planorbis
tvheatleyi Lea. Coosa drainage of Alabama.



98 LAND AND FRESH WATER MOLLUSKS

The lamellation of Segmentina is composed of irregular undulate
ridges, radiating from the axis of the shell. In Planorbula there are
four dentiform lamellae on the outer and two (one quite small) on the
axial side of the throat, in a general way mostly turned in the direction
of the coll, and the earlier series are absorbed as the animal grows.
The position and shape of these lamellae are remarkably uniform in all
the species. In Haldemanina the lamellae are more elongate and com-
plex, requiring a diagram to define their relations, but on the whole
more like Planorbula than Segmentina. (See Binney, Land and Fw.
Sh. N. Am., n, p. 137, figs. 226-7, 1865.)

Segmentina (Planorbula) armigera Say.

Planorbis armigerus SAY, Journ. Acad. Nat. Sci. Phila., n, p. 164, 1818.
HALDEMAN, Mon. Limn., p. 30, pi. iv, figs. 11-13, 1844. GOULD, Inv.
Mass., p. 205, fig. 138, 1841. Type locality, Upper Missouri.

Planorbis armiger BECK, Index, p. 123, 1838.

Range. New England and the Middle States, south to Georgia,
westward to Nebraska, and northward to Great Slave Lake.

Lake Winnipeg and the Saskatchewan River ! Egg Lake, Saskat-
chewan : Red Deer' Battle River; Great Playgreen Lake, Manitoba;

Fort Ellice and Fort Pelly ; Ver-
milion Lake ; Moose Factory ;
Tames Bay ! Fort Resolution, Great
Slave Lake !

FIG. 76. Planar- FIG. 77. Teeth Shell biconcave, of five whorls,
bula armigera Say. of P. -wheatleyi polished, with an olivaceous peri-
*,nat. size;*, teeth Lea, for com- ostra surface sli hd


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