7X LIBRIS

William Healey Dall

Division of Mollusks
Sectional Library

No. IV.

Description of Six New Species of the Genus Unio, embrae-

img the Anatomy of the Oviduct of one of them, together.

with some Anatomical Observations on the Genus. By
Isaac Lea.—Read before the American Philosophical Society
November 2d 1827.

Preliminary Remarks.

EE the present contribution to the science of Conchology, I
have endeavoured to be as brief as I thought the subject
would permit.

Thave often felt the great inconvenience sustained from
too short and indefinite descriptions; and am therefore fully
sensible of the necessity, for the proper distinction of the spe-
cies, of a more minute notice of their characters than is usu-
ally given. In this Mr Barnes has shewn a laudable example,
and he deserves the acknowledgments of the conchologist*.

It will be observed I have followed his plan of dividing the
margin of the disk into eight parts, reversing his posterior and
anterior margins. .

* Swainson says, ‘ Although Lamarck has described so many (Uniones), the
short descriptions he has given, and the want of figures to elucidate them, render it
impossible to determine accurately one half the species which he has enumerated.”

260 SIX NEW SPECIES

The genus Unio, established by Bruguiéres, and placed by
Cuvier* in his fourth class of mollusques, les acéphales, and
second family, acéphales testacés, or the mytilacés; and by
Lamarck in his eleventh class, conchiferes, first order, conchi-
feres dimyaires, thirteenth family, les nayades; is to the con-
chologist one of the most interesting of all the genera. Re-
cent American writers on the subject have added many new
species to this genus, and other new ones are almost daily dis-
covered.

I propose now to add six species, which I believe to be dis-
tinct from any hitherto described. In doing which, I give
very exact descriptions accompanied by drawings, with a
hope they may not hereafter be confounded with other species.

The constant and perplexing changes which the species of
this genus assume have led even the accurate Lamarck inte
the error of describing several varieties as different ‘species;
andit is not without due hesitation and caution that I am in-
duced to add the present. It has been doubtful with some
conchologists whether the species of the genus Unio are not
the mere varieties of one species}. To the naturalist, who has
had the opportunity of examining numerous specimens, the
gradations are so interesting, and at the same time so perplex-
ing, that he is lost in the maze of their changes, and he seeks
almost in vain to draw a distinctive line between them; for
even the tuberculated shells sometimes pass by almost insensible
gradations into smooth ones. Although this line may not
always be satisfactorily drawn, I think their division into spe-
cies should be retained, if it were only for the sake of system.

The comparative anatomist finds in the animal of the Unio
an organization very far advanced towards a state of perfection.
Lamarck places it, in his scale of perfection, higher than in-
sects, and we cannot be surprised at this, when we examine
its structure and find it possessed of brain, heart, branchiz,

* Régne Animal, vol. ii. p. 453. ; :

} The following genera, separated from the genus Unio, dipsas (Leach), hy-
ria (Lamarck), alasmadonta (Say), damaris (Leach), cannot in the opinion of
Mr Swainson retain their station among the genera.

OF THE GENUS UNIO. 261

liver, intestines, and an arterial and venous circulation, so
complete as to excite our greatest admiration.

Taking the natural position of the animal, I have reversed
the anterior and posterior margins as used by Linneus, Bru-
guiéres, Lamarck, Bosc, and others ; and have followed Cuvier*
and Blainville. That margin which has the ligament be-
tween it and the beaks is considered by Lamarck as the ante-
rior margin, but it will be found on examination not entitled
to be so considered, for two reasons: 1. The mouth over
which is situated the brain is placed in the opposite margin.
2. When the animal is in progressive motion, this opposite
margin is always pointed in the direction of its progress. I
therefore follow Cuvier in his anterior and posterior margins,
because they are founded in truth.

A recent and very accurate writer, Blainville, gives us so
simple an explanation of the position in which a bivalve should
be placed, that I am induced to extract it. He says—“ We
suppose the shell to cover the animal, and that it is passing
from the observer, the head (mouth) in front. The beaks
should be above—the ligament between the beaks and the
observer. In this position the opposite side to the beaks
would be the base, and the two extremes of the perpendicular
diameter of this direction would be, the one anterior, the other
posterior.”

Of the habits of this animal we know little; future obser-
vations must open to us an interesting history of them.
With regard to their food, it seems to bea matter of doubt upon
what they subsist. I have strong reasons to believe they feed
upon animalcula, which are ever found to exist in water and
which they might separate from the constant stream, which they
pass from the posterior part of the shell, and which must be
taken in at another part. This interesting operation I witnessed
frequently in a vessel in which I kept them forsome months.
If the water was not changed for twenty-four hours, I uni-
formly found my interesting captives perfectly quiet, but within

* Regne Animal, vol. ii. p. 472.
VOL. I1.—3 U

262 SIX NEW SPECIES

a few minutes after it was changed, they as uniformly com-
menced the passage of this constant stream. I cannot sup-
pose this operation to be for the sole purpose of breathing, as
there is no intermission in the stream of the water, and the
quantity thrown out is too great for this purpose only. 1!
believe it to be the result of the action of the separation of the
animaleula from the water.

Lamarck informs us that the animal of the anadonta (which
is essentially the same with the unio) is hermaphrodite and
seems viviparous; for the eggs pass into the oviduct placed
along the superior branchie, where the young are found with
their shells complete. In the dissection of an anadonta undu-
lata nearly three inches long, I met with the oviducts
charged with about 600.000 (as nearly as I could calculate)
young shells perfectly formed, both valves being distinctly
visible with the microscope.

There cannot be a doubt that the two pairs of muscles,
which support the foot and serve by their alternate action to
give the animal locomotion, are entirely distinct from the
great anterior and posterior muscles, which seem but to serve
the purpose of closing the valves opened by the elasticity of
the ligament. The cicatrices of the muscles of the foot. ante-
riorly, are placed wnder the great anterior cicatrix. posteriorly
over the great posterior cicatrix, and are sometimes confluent
with the great cicatrices, sometimes entirely distinct from
them.

It is necessary to notice here another set of attaching mus-
cles. which seem to have escaped attention. We find, on
closely examining the region of the cardial tooth, a small ir-
regular row of muscular impressions. In those species which
possess large lobed teeth, these will be found generally on the
inner side of them and somewhat underneath. In the more
fragile shells, possessing comparatively small teeth, such as
the alatus, gracilis, &c. we find these impressions in the
cavity of the valve beneath the beaks. To this part of the
shell I found in many species the animal to be quite strongly
attached. It seems to serve to support the mantle, branchiz.

OF THE GENUS UNIO. 263

&e. by the centre, and in this certainly serves a very useful
purpose.

Being exceedingly anxious to examine the animals of the
various species of the Unio from the Ohio, my brother,
T. G. Lea, kindly sent me thirteen species and many varieties,
which, with the assistance of Mr Stewart, were carefully dis-
sected. Those consisted of the species mytiloides and meta-
nevra of Rafinesque; siliquoideus, triangularis. gibbosus and
cornutus of Barnes; purpureus, alatus, ovatus of Say; A¢sopus
of Green ; irroratus and ellipsis now first described. This ex-
amination furnished me with several interesting results. It con-
firmed me entirely in my belief that the oviducts of the irro-
ratus were different from any other species yet examined; a
drawing and description of which will be found in this paper.
The prolongation of the sacks of the oviducts is peculiarly
interesting. In some of the varieties of the cornutus, which
seem to run into the Aisopus, we found the posterior and infe-
rior parts of the shell unnaturally extended. The mark of
the animal on the shell had its usually curved shape, while
the mantle, quite callous, extended to a protruded and irregu-
lar margin.

It has been a matter of speculation how the calcareous
matter was secreted to increase the outer margin of the teeth
as well as their whole surface. In this examination we found
the surface of the broad teeth, some of which were near half
an inch thick, to be completely covered with a prolongation
of the mantle, extending from the great anterior to the great
posterior cicatrix ; so that when the teeth closed they completely
enveloped it. This part of the mantle is exceedingly thin and
transparent.

In the study of this genus, we are naturally attracted
by the beautiful rays which frequently are found in the
epidermis. This to the unpractised eye would seem to
be a sufficiently distinctive characteristic to mark a species.
There is, however, no character more fleeting and various.
The young of many species uniformly possess rays, and we
sometimes find fine adult specimens of extreme beauty. The

264 SIX NEW SPECIES

naturalist is therefore obliged to abandon this character as al-
most useless. In noticing the colouring of the epidermis we
must not pass unobserved the peculiar spots which are found
on the cylindricus of Say, the metanevra of Rafinesque, and
triangularis of Barnes. These have generally the form of
an arrow-head, but sometimes so much elongated as to form
rays. he hair like rays of the cornutus of Barnes and its
varieties are peculiarly beautiful in fresh and perfect speci-
mens; and the spotted lines covering the irroratus over its
whole disk will yield to none of the painted epidermides.

In the measurements I have adopted the plan of Barnes:
the greatest transverse line is the breadth, the greatest line
perpendicular to this is the /ength, and the greatest line per-
pendicular to those lines, that is, from the most ventricose
part of one valve to the most ventricose part of the other, is
the diameter. We thus have the three greatest measure-
ments of the shell, and the marginal descriptions give the
form. It should be remembered that different localities pro-
duce various sizes, and even the thickness of the shell is
frequently changed from this circumstance.

In considering the word “Unio” as of the masculine gen-
der, I have followed the American conchologists, in oppo-
sition to Lamarck and other Europeans, who consider it as
feminine. Ainsworth, in that part of his dictionary ap-
propriated to pure Latinity, gives the following definition :—

Unio, onis, m. (ab unus, quod in conchis nulli duo reperi-
antur indiscreti, 7. e. similes,) 2 pearl, called a union, because,
many being found in one shell, not any of them is like the
other. Plin. 9,35. Unionum conch, mother of pearl. Suet.
Ner. 31.

In Ainsworth’s “Index Vocum Vitandarum” is to be found
the following definition :—

Unio, onis, f (quod unum facit) Union, concord, agree-
ment; the number of one, Theol. (Jn this latter sense ié
must be masculine, as ternio, senio, &c. *J. C.)

* J. C. John Carey, the editor of the last edition of Ainsworth’s quarto dic-
tionary.

at,

Unie

Drew by LLex.

catceolus .

Unio tancecltatus -

Drawn on Stone UPr. by J. Dray tor

OF THE GENUS UNIO. 265

It is evident, that the word explained by the former of
these definitions is the most proper to express a genus of
shells ; and consequently, in Conchology, the word Unio is
masculine.

1. Unto Cauceouus. Plate II. fig. 1.

Testé inequilaterali, transversd, aliquantulim cylindraced, tenuiter
rugata ; dente cardinali prominente.

Shell inequilateral, transverse, somewhat cylindrical, finely wrinkled ;
cardinal tooth prominent.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of Prof. Vanuxem.

Diam. -6, Length -8, Breadth 1-5 inches.

Shell ventricose, cylindrical, transverse—substance of the
shell thin, rather thicker anteriorly—beaks slightly elevated,
undulated and touching; not decorticated—ligament short,
partly concealed by the beaks—dorsal margin straight ; pos-
terior dorsal margin oblique and carinated; posterior margin
angular ; posterior basal margin curved ; basal margin nearly
straight ; anterior and anterior dorsal and basal margins round-
ed—epidermis dark green at the margin and becoming lighter
towards the beaks; rays indistinct—cardinal tooth of right
valve prominent and somewhat pointed; the single tooth of
this valve shuts in before the tooth of the left valve, instead of
passing into it; the tooth of the latter valve is emarginate—
lateral tooth very short and single in both valves—posterior
cicatrices confluent, as are also the anterior ones—cavity of
the beaks deep—nacre pearly, white and silvery, iridescent in
the posterior margin.

Remarks.—This curious little shell is peculiar in its promi-
nent curved tooth, shutting in before that of the other valve.
VOL. 11.—3 X

266 SIX NEW. SPECIES

Its nacre is uncommonly silvery. It swells considerably along
the posterior umbonial slope. This causes its greatest diame-
ter to be semidistant between the beaks and posterior margin.

I have given a view of the right valve of this shell for the
purpose of exhibiting its remarkable tooth. It might at first
be considered as a malformation, but in the three specimens
which I have seen this character has been uniform.

The calceolus approaches as nearly in its general appearance
to the donaciformis as to any other species. It is however a
thinner shell, and differs in the teeth as well as the colour of
the epidermis.

2. Unto Lanczouatus. Plate III. fig. 2.

Testa transversim elongata, compressa, postice subangulata ; valvulis
tenuibus ; umbonibus vix prominentibus ; dente cardinali acuto, obliquo.

Shell transversely elongated, compressed, subangular behind; valves
thin; beaks scarcely prominent; cardinal tooth sharp, oblique.

Hab. Tar River at Tarborough.
My Cabinet.
Professor Vanuxem’s Cabinet.
Cabinet of the Academy of Natural Sciences.
Mr Nicklin’s Cabinet.
Peale’s Museum.

Diam. °5, Length -7, Breadth 1:7 inches.

Shell transversely elongated, elliptical—substance of the
shell rather thin—hbeaks scarcely elevated, decorticated—liga-
ment small, terminating between the beaks—dorsal margin
slightly curved; posterior dorsal margin carinated; posterior
margin subangular ; posterior basal and basal margins curved ;
anterior and anterior dorsal and basal margins rounded—epi-
dermis lemon-yellow and olive-yellow, with transverse lines
of growth, glabrous—cardinal tooth compressed, crenulated
and oblique—lamellar tooth straight, long and rather abrupt
—posterior cicatrices confluent, anterior cicatrices distinct—

(om oy)

Unio donaciformis.

Unio eblipsis 5

Drawn by TLew Drawn on Stare & Prby Drayton.

IV

OF THE GENUS UNIO. 267

cavity of the beaks shallow—nacre salmon colour and irides-
cent; colour stronger under the beaks, from which beautiful
fine rays diverge to the margin.

Remarks.—-This species, which I have seen only in Tar
River, N. C., approaches more closely to the unio picto-
rum of Europe than any yet discovered in this country.
When I first found it, I felt assured it was the same; but
upon closer examination and comparison find it to be essen-
tially different. The cavity of the beak is much less and the
cardinal tooth shorter and more lobed.

3. Unto Donacirormis. Plate IV. fig. 3.

Testa inequilaterali, transversd, cuneatd, rugaté ; dente cardinali pro-
aminente ; umbonibus posticée angulatis ; margine dorsali posteriori sub-
carinata. .

Shell inequilateral, transverse, cuneiform, wrinkled; cardinal tooth
very prominent ; beaks angular behind ; posterior dorsal margin subca-
rinate.

Hab. Ohio. T. G. Lea.
_ My Cabinet.

Diam. -7, Length 1-0, Breadth 1:5 inches.

Shell not very thick, rounded before and pointed behind—
substance of the shell not thick—hbeaks slightly elevated, not
decorticated, almost touching ; angulated by an oblique carina
passing from the beaks to the posterior margin; this causes a
slight concavity from the beaks towards the posterior mar-
gin—ligament passing to the point of the beaks—dorsal and
posterior dorsal margins slightly curved, the latter sub-cari-
nate ; posterior margin acutely angular ; posterior basal mar-
gin nearly straight; basal margin curved; anterior and ante-
rior dorsal and basal margins rounded—epidermis olive, with
green rays diverging from the beaks to all parts of the mar-
gin; surface glabrous and slightly wrinkled; has distinct

268 SIX NEW SPECIES

marks of growth—cardinal tooth large, prominent, serrated ;
in the left valve deeply divided by the entering of the oppo-
site tooth—lateral tooth abrupt—posterior cicatrices distinct,
anterior cicatrices also distinct—cavity of the beaks rather
deep—nacre pearly white and iridescent in the posterior mar-
gin.

Remarks.—The characteristics of this little shell are its
angulated posterior slope giving it in some measure the form
of a donax, and its large divided cardinal tooth. Its beautiful
angulated beaks approach so closely together as scarcely to
admit the edge of a piece of fine paper.

In its most prominent character, the peculiar angulated
slope, it most resembles the ovatus of Say, but differs greatly
in the size, the ovatus being four or five inches in breadth,
and very much more inflated. The latter has a double car-
dinal tooth in each valve ; RE donaciformis only in the left
valve.

eee!

4. Unio Exxipsis. Plate IV. fig. 4.

Testa figuram ellipseos habente, longitudinali, ventricosa ; valvulis
crassis, umbonibus feré terminalibus ; dentibus grandibus et distinctis.

Shell elliptical, longitudinal, ventricose ; pales thick; beaks nearly
terminal; teeth large and well defined.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of Mr Nicklin.
Peale’s Museum.
Cabinet of the Academy of Natural Sciences. |
Diam. 1:3, Length 1-7, Breadth 2-3 inches.
Shell very thick, ventricose, margin elliptical—substance
of the shell thick and ponderous—beaks thick and projecting

Unite etrorais

Drawn by LLea J. Drayton Ag

OF THE GENUS UNIO. 269

beyond the margin, nearly terminal, decorticated—ligament
partly concealed by the beaks—epidermis reddish-brown,
smooth—surface somewhat wrinkled—cardinal tooth thick,
elevated, compressed at top, crenulated ; direction same as la-
teral tooth—lateral tooth long, thick and slightly curved, ab-
rupt—posterior cicatrices distinct, as are also the anterior ones
—cavity of the beaks small—nacre pearly-white, silvery and
iridescent in the posterior margin.

Var. a—red inside, rare.
Cabinet of the Academy of Natural Sciences.
My Cabinet.

Remarks.—The ellipsis approaches somewhat to a variety of
the mytiloides of Rafinesque, but is more swollen and ponde-
rous, and differs in always having an elliptical margin.

5. Unto Irroratvs. Plate V. fig. 5.

Testa inaquilaterali, sub-orbiculatda, longitudinali, tuberculata, rugosa,
longitudinaliter uni-sulcata ; dente lateralt abrupté terminante.

Shell inequilateral, suborbicular, longitudinal, tuberculated, wrinkled,
longitudinally sulcated ; termination of lateral tooth abrupt.

Hab. Ohio. T. Bakewell.
~My Cabinet.
Cabinet of T. G. Lea. ors
Cabinet of Prof. Vanuxem.
Cabinet of the Academy of Natural Sciences.
Mr Nicklin’s Cabinet.
Diam. 1:3, Length 1:8, Breadth 1-6 inches.
Shell extremely thick and swollen—nearly round, slightly
elongated—substance of the shell thick and ponderous—beaks
somewhat elevated and recurved, decorticated—dorsal mar-
gin rounded; posterior, posterior dorsal and posterior basal
margins rounded ; basal margin slightly emarginate ; anterior
VOL. Ill.—3 ¥

270 SIX NEW SPECIES

and anterior basal margins rounded; anterior dorsal margin
slightly rounded—epidermis yellow, but filled completely
over with numerous dark green spotted lines, running in a
sweep from the beak to the margin. In the anterior part
the crowding of these lines generally forms five or six bands,
the largest being in the furrow in the middle of the-shell; in
the posterior part there are no bands—disks transversely and
deeply wrinkled, with a slight longitudinal furrow from the
beaks to the basal margin—tubercles slightly elevated and nu-
merous, and generally situated on the wrinkles; cardinal
tooth wide, depressed and sulcated; lamellar tooth slightly
curved, thick, rather depressed, short and abrupt—posterior
cicatrices very distinct, the smaller one being placed directly
over the larger one and beneath the point of the lamellar.
tooth—anterior cicatrices distinct, the great one deep—cavity
angular and exceedingly small for the size of the shell—na-
cre pearly white and silvery.

Remarks.—The very minute and delicate spotted lines
which pass from the beaks to the margin of this species well
characterize it. They are so fime and approach so nearly to
each other as to give a general olive appearance to’ the disk,
the ground of which is really yellow. Ihave not observed
this to pervade completely the surface of any other spe-
cies, and in this it is constant. The substance of the shell is
exceedingly massive and ponderous, more so for its size than
any other species which I have seen. The animal is the only
one in the organization of which, during my examination
of this genus, I have been able to detect any essential differ-
ence. From the shell being longitudinal and peculiarly mas-
sive, we might be led to suspect a conformation different from
the other species, and such is the case. ’

By the exertion of my brother T. G. Lea, I have been for-
tunate enough to obtain three individuals of this species in a
state of impregnation considerably developed. In those I ob-
served an appendage, in form of a depressed cone, attached to
the branchie on either side, and a very slight examination
fully satisfied me these were the oviducts. ;

OF THE GENUS UNIO. Q71

In all the other species which I have examined I have found
the ovaries and oviducts as described by Cuvier, Bose, Ca-
rus, &c. The oviducts in these lie in a direct line between
the two great muscles, and are attached to the upper pair of
branchie. In the irroratus this space is so small, as is also
the cavity, that it seems to require adifferent conformation to
accommodate the oviducts, and thus we find them pendent,
and not placed along the plane of the branchie. The long
sacks containing the ova are inserted about half way up the
branchize and somewhat posterior to the centre. The num-
ber of these sacks in my three specimens consists of eight in
two, and seven in the other. ‘The posterior sack is the outer

. or surrounding one, and measured two inches ; the second and

fourth 2:2; the third 2-4; the fifth 1-9; the sixth 1-6; the
seventh 1-4. In diameter the sacks are nearly the same size,
the interior ones being rather smaller than the exterior, which
measures one-twentieth of an inch.

These measurements were effected by separating the mem-
branes which connect the sacks together and stretching them
out. The diameter of the cone is -6; its elevation -2 of an
inch. The outer sack terminates after making one revolu-
tion; the second advances one-third on the succeeding revo-
lution, and each succeeding one obeys the same law until the
last terminates in the centre, and the mass having performed
three revolutions, the whole forms a depressed cone.

This curious arrangement of the sacks to form the depres-
sed cone, which has its base resting on the region of the sto-
mach, is admirably calculated by the economy of nature to
harmonize with the construction of shell, which presents
only at the centre of its disks room for the essential purpose of
propagation. See plate V.

Fig. 6 represents the interior, fig. 7 the exterior of the ovi-
duct, the mantle being removed.

a the mouth.

6 the great anterior muscle.

e the superior right branchie.

ae

272 SIX NEW SPECIES

d the great posterior muscle.
e the inferior right branchiz.
f the right oviduct. Ka
g the foot.

h the superior left branchie.

7 interior view of the oviduct.

6. Unto Lacrymosus, Plate VI. fig. 8.

Testa sub-quadrangulari, inequilaterali, posticé angulatd, transversa,
tuberculata ; dente laterali abrupte terminante.

Shell subquadrangular, inequilateral, angular behind, transverse, tu- —
berculated ; termination of lateral tooth abrupt.

Hab. Ohio. 'T. G. Lea.
; My Cabinet.
Cabinet of T. G. Lea.

Cabinet of Prof. Vanuxem.
Diam. -9, Length 1-7, Breadth 1-8 inches.
Shell rather depressed and rounded anteriorly—substance-
of the shell thick—beaks slightly elevated with the ligament
passing between them, recurved and almost touching, free
from decortication, and covered with beautiful delicate raised
points—when viewed on the back all the visible part is co-
vered with them—dorsal margin oblique; posterior dorsal
margin subangular, carinated ; posterior margin angular ; pos-
terior basal margin emarginate; basal, anterior and anterior
dorsal and basal margins rounded—epidermis yellow-green
and very smooth, almost white at the point of the beaks, an-
teriorly slightly rayed—disks tubereulated, having a smooth
channel, margined by two rows of tubercles or raised points,
running from the point of the beaks, and diverging one to the
basal, the other to the posterior margin—tubercles, enlarging
towards the base, taking the form of flowing tears,and resem-
bling coagulated gum ; they are very minute at the point of the
beaks—undulated delicately along the posterior dorsal mar-

VI

Creo lCaerymasias

LDraun by 1 Lea. A Pravtan Ag f.

OF THE GENUS UNIO. 273

gin—have one distinct line of growth—cardinal tooth very
wide, depressed and sulcated—lamellar tooth straight, short,
crenated and abrupt—posterior cicatrices confluent; anterior
cicatrices distinct, the great one deep and partly surrounding
the cardinal tooth—cavity not deep, but angular, and extend-
ing under the cardinal tooth—double impression of the man-
tle very perceptible—nacre pearly white and silvery.

Remarks.—This rare shell forms without doubt the most
beautiful and perfect species yet discovered of this genus. Its
beautiful tubercles, lively colour and delicately pointed white
beaks, together with its strikingly pure nacre, entitle it to a
precedence over all that have yet found their way to our ca-
binets. The form of the tubercles is very peculiar and they
distinctly mark this fine species. ‘The specimen represented
in the drawing is the largest of five which I have seen.

This species is more nearly allied to the metanevra of
Rafinesque than to any other. It differs however, essen-
tially, in its having a greater number and more distinct tuber-
cles; its colour, and the tuberculous ridge of the latter being
replaced by a smooth furrow, enlarging from the beaks to the
posterior basal margin and bordered by two rows of small tu-
bercles.. The metanevra is also larger and more ponderous,

VOL. 11.—3 Z%

No. V.

On the Geographical Distribution of Plants. By C. Pick-
ering, M.D.—Read October 19th 1827.

fe observations of travellers in every part of the globe, and
our greatly increased knowledge of the species both of ve-
getables and animals, have of late years brought forward the
interesting subject of their geographical distribution. The
materials accumulated prior to the last half century were few,
and insufficient to solve many questions which have since
yielded to the labours of naturalists. Much has been accom-
plished by Humboldt, Brown, Schouw and others—the sub-
ject is continually receiving increased attention, but it is uni-
formly rendered intricate by attempting to reduce under the
same laws both species and groups (as families, genera, &c.),
while it is evident that the local causes, which, in the one in-
stance, greatly influence their distribution, by no means affect
the other. In this essay, species and groups are examined
separately, the inquiry is directed more particularly to the
former, and their range is followed as a guide in the arrange-
ment here proposed.

Solar heat is evidently the principle which puts in motion
the fluids of plants, and these vary in their relation to it,
some requiring a temperature that destroys others; conse-
quently, a plant being carried far north or south of its natural

No. XIII.

Description of a New Genus of the Family of Naiades, inclu-
ding Eight Species, Four of which are New ; also the De-
scription of Eleven New Species of the Genus Unio from
the Rivers of the United States: with Observations on some
of the Characters of the Naiades. By Isaac Lea, M.2.P.S.
MANSP., §c. Read March 6th, 1829.

i] HAD the pleasure to present to this Society in November,
1827, a description of six new species of ‘the genus Unio,
which they did me the honour to publish. Since that period
I have continued to collect and examine the genera of the
family of Naiades with great interest, and more success than
I could have anticipated. I propose in this paper to describe
fifteen new species, a number which rarely falls to the lot of
a naturalist at one period ; and I shall previously indulge my-
self in some observations respecting their characters, ha-
bits, &e.

Strong objections have been made to the study of concho-
logy by persons unacquainted with this branch of zoolog
and it has been alleged that a collection of shells is merely
a collection of the houses or habitations of an animal carefully
removed by the naturalist or destroyed by other causes, and
therefore unworthy the time and attention of the student of
nature. This assertion betrays ignorance, and recoils on the
observer ; for it may with truth be said, that no part of the

VOL. Ill.—5 K

404 NEW GENUS AND SOME NEW SPECIES

works of nature, however minute or unimportant to the pas-
ser by, can be examined without creating in the student of
nature the utmost wonder and astonishment.

In this class of animals nature seems not to have worked
with the hand of a stepmother; she put them out of her lap
after having Javished her bounties upon them in the utmost
profusion. All the tints and combinations of the colours of
the rainbow are called to adorn their coverings; and in the
form of the shells we have almost all the figures that the
science of geometry can present. Who can watch the com-
mon snail of our woods, and see him commence at a mere
point, from which he builds his covering by a secretion from
his own body and turns it with the most mathematical exact-
ness, without exclaiming, Thou art indeed a great geometri-
cian! and when he comes to finish his arched entrance, graced
with a curvation pure and as white as marble, who can
refuse to acknowledge him an accomplished architect?

In viewing the covering of this class of animals, I consider
it as in some measure analogous to the skeleton in the
vertebral animals. The muscular attachments, of which
there are many, to the two valves of the conchifera, may be
viewed as the attachments of the muscles of the animal frame
to the bones, by which we are enabled to enjoy locomotion.
The ligament, which firmly connects, exteriorly, the two
valves, may be assimilated to those ligaments whose almost
exclusive service is to connect some of the important bones
of the human skeleton.

Is it reasonable to consider the valves as merely a habitation
for the animal? Are they not always acting a more distin-
guished part? The ligament, beautifully formed of a com-
bined horny and fibrous substance, is ever in action while the
animal lives, and this action is counterbalanced by the con-
traction of the muscles attached to the interior of the valves.
The epidermis too has its duty to perform in protecting from
decomposition the calcareous matter of the shell. It is com-
posed of a thin horny substance—somewhat like that of the
exterior part of the ligament. The prolongation of the epi-

OF THE FAMILY OF NAIADES. 405

dermis beyond the margin of the shell seems well adapted,
when the animal closes the valves, to exclude the entrance of
water, &c., and doubtless is thus used.

When a conchologist examines a shell which to him is
new, almost the first question he puts to himself is, “what
must be the form of the animal which once inhabited this
covering?” He judges by analogy; and after examining the
form of the shell, he has generally a very good idea of its for-
mer inhabitant, and although he may not be able to decide
with the same precision as the osteologist, he can place it in
its proper family.

Each family has a form of shell adapted to the wants of
its inhabitant, and peculiarly fitted for its locomotion or its
fixed situation. Thus the Ostracea could not exist in the
shells of the Naiades, although the forms of the animals are
not very dissimilar to the unpractised eye. The naturalist,
however, sees in the former the entire want of the muscular
foot for locomotion and its attendant pairs of muscles. In the
valve of this he sees but one muscular impression, which
muscle is used for the sole purpose of closing the valves, while
in the other he sees at least four, two of the muscles of which
are used for protruding, the other two for retracting the foot
by which it propels itself. The species of the family Myti-
lacea attach themselves by a strong byssus to stones, &c., and
therefore require a very differently constructed shell. The
Lithophaga bore into stone, wood, mud, &c., and have no
power of locomotion. 'The Solenacea generally live in pits,
and move only between the two extremities of them. To
these families might be added many more, all of which are
as different in form and habits, as can well be imagined. It
may therefore be safely asserted that the student -of concho-
logy can always form some idea of the animal from the form
of the shell.

My attention having been particularly drawn to the study
of the family of the Natades, and my cabinet possessing a
great number of species and varieties, I feel induced in this
preliminary matter to say something on the species of the

406 NEW GENUS AND SOME NEW SPECIES

Uniones, described by naturalists who have written on our
shells.

The genus Unio presents in the waters of the United
States, particularly in the rivers west of the Alleghany moun-
tains, a number of species almost extending beyond belief.
Nature has scattered them here with the hand of profusion,
after having formed them with the most harmonising beauties.

The number of the species adds greatly to the difficulty of
distinguishing them, for they glide into each other so insensi-
bly through their varieties, that the most experienced are often
at fault and perplexed with the difficulty of placing them pro-
perly in the most approved systems*. But, although we may
at every step meet with these difficulties, I cannot suppose that
most of those described as species do not exist; the fault has
been that mere varieties, in the eagerness of authors to make
species, have too often been erected into species, and the great
Lamarck has committed this error in as great a degree as
almost any other writer.

It is the opinion of some eminent conchologists that the
family of the Jaiades possesses but one genus, and that the
genera into which it is at present divided are only species,
and the species varieties. Were we to adopt this division, we
should be in a worse dilemma than before ; for we can scarcely
imagine bivalves more different from each other in form than
are some of our trans-Alleghany species of Unio.

How totally different is the rectus of Lamarck from the
irroratus ? (nobis). The first is four times the width of its
length, whilst the latter is longer than broad. The one is
broad rayed, in fine specimens; the other possesses dotted
lines universally. The triangularis of Barnes is entirely
dissimilar to the nasufus of Say, as is also the circulus,
herein described, from the /anceolatus (nobis); and the same
may be said of peruvianus and pictorum. ‘Two species could

. id . .
* Swainson says, ‘* Indeed so much uncertainty hangs on the shells of this ge-
nus, that the species can only be fixed by ample descriptions and very correct
figures.”’—Zool. Illus. Vol. I. t. 57.

OF THE FAMILY OF NAIADES. 407

be scarcely more unlike than the smooth and radiated s#li-
quoideus of Barnes and the beautiful tuberculated lacrymo-
sus (nobis); and the same remark may be applied to the
cylindricus and alatus of that excellent conchologist Mr Say.
Many other species could be thus contrasted, but I deem the
above sufficient, upon examination, to prove the justness of
my remarks, and the necessity, in the present state of our
knowledge, to retain the species, whatever may be the changes
in the genera*. as

In a preceding paper on the Uniones I said something on
the habits of the animal. I wish now to mention the simple
fact that I have kept several specimens about ten months in
a basin changing the water every five or six days. During
this period they passed through the winter without any
change in their usual habits, and nothing in the shape of food
was given during the whole period.

This truly interesting family presents us with very diffi-
cult specific characteristics, rendered so by the species con-
stantly approaching in similitude to each other, and by the
change made in them by age, locality, and exposure.

I propose to offer a few observations on the principal cha-
racters, in which it will be seen how little we can depend on
any one of them, and shall begin first with the teeth.

Tecth. n the species of the Unio these have been used as

* Ina letter addressed to me by William Cooper, Esq., an intelligent natu-
ralist of New York, he says, ‘‘ There are now, I think, not less than thirty North
American species of Unio well established, and perhaps seven or eight more.
That they are species, each perpetuating its peculiar form, subject to certain va-
riations, but permanent within fixed limits, seems to me the most rational opinion,
although some of our most judicious naturalists think otherwise. Your account
of the animal of the U. irroratus affords a strong argument in favour of this belief,
for it proves that to be beyond doubt as distinct a species as any in any class of
animals. Yet this may always be known with certainty by the shell, which,
though so well characterised, is not, however, more different from the rest of the
genus, than they are from each other, and frequently still less so. If, therefore,
this difference is found to be constantly indicative of a species in one instance, it
must also be in others. I believe that our lakes and rivers contained the same
form of shells at the creation and ever since that they do at this day. If they are
hermaphrodite per se, as is said of them, it could not be otherwise ; and if the
contrary were admitted, natural history would not deserve the name of a science.”

VOL. 11l.—95 L

408 NEW GENUS AND SOME NEW SPECIES

strongly characteristic, but we cannot place much reliance on
this character, unless accompanied by and dependent on others.
Thus, the angle of the cardinal tooth depends much on the
location of the beaks, and we know that in the same species
the location is quite different, and yet this difference is not
worthy of creating even a variety. If the beaks be placed
immediately over the anterior margin*, as in the ellipsis they
generally are, then the cardinal tooth will be nearly or quite
parallel to the lamellar one ; but if the beaks be more posteriorly
placed, then the cardinal tooth becomes more oblique. We
must, therefore, when characters are so difficult, look at them
in combination, and adopt them with due consideration.

In the same species the mass or substance of the valves
varies much according to localities. Thus we find the com-
planatust in some of our Atlantic rivers full grown, when
only an inch broad, while in other of our Atlantic rivers
we have them four inches broad. In some localities we
have them possessing but little calcareous matter, while in
others they are almost massive. ‘This also occurs in per-
haps a greater degree with some of the western shells. And
if we examine a massive specimen, we are almost sure to find
the cardinal teeth more or less thick, whilst those of the same
species which are thin, and they frequently differ very
much in this respect, will be found to possess cardinal teeth
of quite a crested structure. The cardinal tooth, being single
in one and double in the other valve, or double in both valves,
cannot be depended on as an unfailing character. ‘The same
species will often present double teeth in both valvés, although
it may be usual to possess them in the right valve only. The
lamellar tooth depends much on the substance of the speci-
men. If it be massive the teeth will be thick, if thin more
bladed ; the teeth, therefore, differ almost as much in varieties
as in species. We must, consequently, while examining a
specimen to determine its species, give due attention to these
counteracting characters.

* T reverse Lamarck’s anterior and adopt Cuvier’s as heretofore,
| Purpureus of Say. ;

OF THE FAMILY OF NAIADES. 409

Colour. The colour of the Uniones is generally a decep-
tive character. This, however, is not always the case, and
therefore it deserves the attention of the conchologist. In some
species it is permanent in the nacre, in others it is permanent
in the epidermis. In the following species I have always found
the nacre to be white and pearly, viz. cornutus, tubercula-
tus, siliquoideus, ventricosus, ovatus, triangularis, parvus,
plicatus, metanever, xsopus, scalenius, cylindricus*, lacry-
mosus, irroratus*, ellipsist, donaciformis, calceolus, hetero-
don, multiradiatus, occidens, securist, iris, zig-zag, patulus,
and planulatus: the last eight herein described. In the
“torsa” of Rafinesque, and sulcatus (herein described), the
purple is permanent and generally dark. In the suwbten-
tus, lanceolatus, and rubiginosus (herein described), it is a
pale salmon colour, and in the afer (herein described) it
is a pink bordering on purple. The gibbosus is generally a
dark purple or chocolate, but varies from this through all the
intermediate shades to perfect white. The verrucosus is
either chocolate or white, and does not seem to enjoy the in-
termediate tints. The circulus (herein described) is gene-
rally of a pure pearly white, but sometimes, though rarely,
possesses a blush of pink in the centre of the valve. The
mytiloides presents all the shades from the deepest flesh co-
lour to the purest white. The cariosus is generally white,
but sometimes is found of a deep salmon and the intermedi-
ate shades. The nasufus is either pearly white or approach-
ing salmon colour under the beaks. The rectus is gene-
rally of a beautiful porcelanic white, sometimes tinted about
the cardinal teeth and in the cavity of the beaks with purple

* The cylindricus and irroratus sometimes, in very perfect specimens, present
a slight golden appearance in the nacre at the anterior margin.

t Var. a being herein described as a new species.

{ This is Rafinesque’s ‘* U. depressa,’ but the name being preoccupied by
Lamarck, apparently without the knowledge of Mr R., I am compelled to give it
a new name or leave it out of the catalogue. I prefer the former alternative, as
it is a distinct and beautiful species, and well known to most of our conchologists
under its duplicated name “ depressa.”’ In this I act in accordance with the
rules of nomenclature in natural history. See description.

410 NEW GENUS AND SOME NEW SPECIES

or salmon, more generally the former: specimens are rarely
found with the nacre entirely coloured. The complanatus,
of which so many false species have been created by Euro-
pean naturalists, presents us with more colours and shades
than any other species except the cuneatus of Barnes, which
by many conchologists is considered analogous to it. These
two species present us with specimens of the darkest purple,
the purest white, the richest salmon, and all their intermediate
shades. The fine indistinct stria of the nacre, which are
sometimes observed to diverge from the interior of the beak
to the margin, are caused by the successive removals of the
marginal attachment of the mantle.

It should be borne constantly in mind that the colour of
the nacre is an extremely doubtful character in the family
of Naiades; in exemplification of which I have an Anodonta
from the Ohio, the nacre of one valve of which is salmon and
the other white. 'The valves are beyond all doubt of the same
animal. The green irregular spots and marks sometimes de-
scribed to exist in our Uniones deserve no attention, as they
are altogether accidental, perhaps the effect of disease: they
are more frequent in the rectus and cylindricus.

Elevations on the surface of the disks. _'These are sometimes
tuberculated, sometimes undulated; and our western waters
are the only ones we know of which produce many species thus
marked. There they exist in great variety and exceedingly
great beauty. The U. tuberculatus and U. lacrymosus pos-
sess more tubercles than any other species. 'The U. verru-
cosus possesses them irregularly scattered over the sides of the
valves. The U. metanever and U. cylindricus, besides the
irregular elevations over the disk, have remarkable undula-
tions along the umbonial slope*, from the beak to the mar-
gin. The WY. cornutus is furnished with three or four protu-
berances or “horns” in a row, passing from the beaks direct
to the basal margin; the varieties of the cornutus have these

* I use this term for the elevated ridge which passes from the beaks to the pos-
terior margin.

OF THE FAMILY OF NAIADES. 411

“horns” more depressed and more frequent, and thus pass
into varieties with a mere furrow without any distinct eleva-
tions, and these gradations are almost innumerable. The
wroratus has slightly elevated tubercles along both sides of
the furrow; these are sometimes continued along the wrin-
kles, making them elevated. The exsopus has a “nodu-
lous ridge” over the middle of the shell, and the plicatus
has folds or waves over the posterior part of the disks, more
or less numerous, and which are so large as to produce an
irregular effect through the nacre in many instances.

The epidermal colours of this family are exceedingly cir-
cumscribed. The ground varies from deep fuscous or black
to pale yellow, frequently passing through obscure green,
rarely bright green. This ground is intersected frequently
with rays or spots of a darker hue. In fine and perfect spe-
cimens these are generally perceptible, sometimes eminently
beautiful. In imperfect or old specimens these marks are
almost always obliterated. The following species, when the
specimens are perfect and fresh, occur beautifully painted
with rays more or less broad: viz. complanatus, cuneatus, ra-
diatus, siliquoideus, ventricosus, ovatus*, cariosus, nasutus,
lacrymosus (very slightly), calceolus, rectus, ochraceus, hetero-
don, sulcatus, multiradiatus, occidens, tris, and zig-zag.

The securis is rayed in a manner peculiar to itself. (See
description.) The cornutus has beautiful hairlike lines, some-
times minutely waved, which diverge to its entire margin.
Some of the varieties have no rays, while others have compa-
ratively broad and beautiful ones. The sulcatus is indistinctly
rayed over the umbonest, but the furrow passing from the
beaks to the posterior basal margin has many hair like lines,

* Mr Say says this shell is “not radiated.” This is generally the case: but
some specimens are beautifully rayed ; and Lamarck says of his var. b, ‘‘ testa ra-
diis longitudinalibus picta.”’

} I use this term as Linneus did: it is the ‘ ventre’’ of the French writers.
Draparnaud says, “la portion la plus renflée des valves.”’ It is improperly used
by English writers denoting the beaks or summits.

VOL. 11.—5 M

412 NEW GENUS AND SOME NEW SPECIES

which are minutely waved; these lines are continued over the
umbonial slope. The ¢rroratus is covered over the whole
disk with dark green spotted lines, running in a sweep from
the beak to the margin and lying close to each other.

The following species have broad interrupted rays, which
in some instances make rows of square spots : viz. planulatus,
scalenius, verrucosus (when young), and patulus.

The donaciformis and zig-zag have diverging rays formed
more or less distinctly by zig-zag lines. The cylindricus,
metanever, and triangularis are smgularly and most beauti-
fully marked with dark green spots in the form of an arrow
head, the point directed to the margin. The first and last
possess the most; in the others it can only be distinguished
in very fine or young specimens. ‘The marks sometimes ex-
ist in a confluent state, and rays are consequently produced.
They are most prevalent in the cylindricus, and vary from
the length of a quarter of an inch to a mere point; in the ¢ri-
~angularis they are more generally confluent. Some speci-
mens of cylindricus are so much charged with these arrow-
headed marks as almost to obliterate the yellow ground of
the epidermis, and cause the valves to appear at first sight of
an uniform dark green.

The remainder of the American species described are with-
out epidermal markings, and I shall divide them, as it is ex-
tremely difficult to designate their shades, into blackish,
brownish, and yellowish. The afer, tuberculatus, cireulus,
and cibbosus* are blackish. The cireulus i is peculiar in hay-
ing the posterior slope yellowish. The parvus, torsus, plica-
tus, myliloides, xsopus, subtentus, verrucosus, ellipsis, rubi-
ginosus, are brownish. Some of these, however, vary much.
The forsus is found sometimes yellowish, and when young
almost black; the posterior slope is, however, universally
yellowish. Large and old specimens of the plicatus are
quite black; the young are light brown. In the myfiloides

* The young gibbosus is sometimes very obscurely rayed.

OF THE FAMILY OF NAIADES. 413

the young specimens are sometimes rayed over the umbones.
The young xsopus is bright yellow and highly polished. The
young verrucosus has sometimes one or two broad interrupted
green lines over the middle of the umbones. In young or
very perfect specimens of the ellipsis may be seen numerous
small rays passing over the umbones towards the posterior
margin. In the younger specimens of the rubiginosus indis-
tinct rays are sometimes seen. The /anceolatus is yellowish
passing into olive.

It should ever be borne in mind, notwithstanding what
has been said above, that colour is exceedingly deceptive, and
may often lead to error. It is impossible to find permanent
characteristics in it, on which we can universally depend, as
locality, exposure, youth, and age so materially affect its ap-
pearance. We must therefore consider it in most cases as
only auxiliary, though in a few cases it is permanent.

Beaks. Lamarck, in his generic description of the Unio.
says, “natibus decorticatis, suberosis.” This character is not
permanent by any means in our species, some of which are
almost universally found free from decortication, while others
are partially so; and others again rarely free from it. The
objection to receiving it as a permanent character even in spe-
cies is, that more or less exposure to the action of the stream.
&c. will cause the beaks to be more or less eroded in the spe-
cies where erosion takes place. Some species, however, seem
to resist this erosion with great success, owing, as I appre-
hend, to the peculiar firmness of the texture of their epidermis,
which certainly differs in different species. I have never
seen either of the following species eroded, viz. U. parvus, U.
calceolus, U. lacrymosus, U. rubiginosus, or the Symphynota
levissima (the two last herein described). It is rarely we see
a ponderous shell free from this erosion, and the U. cylindri-
cus seems to be peculiarly subject to it, for the form of the
beaks can rarely be even traced, yet the largest specimen in
my cabinet, nearly five inches broad, possesses the epidermis
untouched on this part. The beaks of many of the species,
when found in a perfect state, are crowned with concentric

414 NEW GENUS AND SOME NEW SPECIES

undulations or slight elevations, which should always be no-
ticed, as they are highly characteristic. The situation of the
beaks, when peculiar, should have the student’s attention.
They are sometimes almost medial, as in the U. irroratus, U.
circulus, U. laerymosus, §c.; while in the U. ellipsis, U. sca-
lenius, U. cylindricus, Symphynota tenuissima*, §c. they are
almost terminal: this character, however, varies. (See ob-
servations on the teeth.)

The margins or circumference should have our attention
in examining aspecimen. The general form of the Naiades is
ovate, modified into rhomboidal, triangular, circular, and ellip-
tical ; but these formsin the same species will frequently vary,
and therefore must not be entirely reliedon. The U. siliquot-
deus is generally subangular posteriorly, but it is sometimes
truncate, and the U. cariosus is found in the same way. We
find very few species that are constant in this character; this
accounts for the many species created from the U. pictorum
in Europe.

Muscular impressions. 'These are important, and should
always have our attention in examining a specimen. But
even this character is not infallible. It should be understood
that the animals of this family always possess two pairs of
muscles, used for locomotion, and placed near or in contact
with the two adductor muscles, used solely for closing the
valvest. In the anterior margin these are generally sepa-
rate, in the posterior more generally confluent; but in the
same species we sometimes find individuals presenting two,
sometimes three, and sometimes four cicatrices, besides
those of the cavity of the beaks; and this depends in a
great measure on the thickness of the shell. If the spe-
cimen -be ponderous, we often find the posterior mus-
cle of the foot attached to the side of the lamellar tooth
near to its termination; if it be thin, although of the same
species, it will be found generally confluent or near to the
great posterior muscle. The cicatrices, made by the attach-

* Herein described.
+ See my description of new Uniones in this volume.

OF THE FAMILY OF NAIADES. 415

ment of the superior part of the mantle in ponderous shells,
generally will be found on the under part of the cardinal
tooth. Sometimes six or eight may be found; and their di-
rection is towards the lamellar tooth. In thin shells these
cicatrices will be found in the cavity of the beaks, generally
traversing it in an oblique direction*.

Ligament. This part of the shell must be viewed with
the same doubt as the above character. In the same species
the ligament may be long and narrow if the specimen be
elongated and thin; and it may be short and thick if it be pon-
derous and obtuse. Thus we may find in an elongated sili-
quoideus the ligament an inch and a quarter long, and only
one-tenth of an inch broad, while in an obtuse and ponder-
ous specimen it may be found to be only three quarters of an
inch long and yet one-eighth of an inch broad, as is the case
in some specimens of my cabinet.

It has been a desideratum with the American concholo-
gists to fix the nomenclature of this interesting genus, parti-
cularly so far as relates to our own species. In the hope of
contributing in some measure to so desirable an object, I
have carefully examined all that has been published on the
subject so far as I could procure the descriptions, and with
diffidence give the results, hoping my views may not be found
to be incorrect.

The first column contains the species, the nomenclature
of which is now likely to be permanent and fixed. The se-
cond the species described by other writers, which are either
the same or varieties, and consequently synonymes.

i 1. radiata, Lam.
1. U. radiatusf, Gmelin, 2. virginiana, Lam.
3. radiatus, Barnes.

* See my description of new Uniones in this volume.

{ Lister (t. 152, f. '7.) gives a correct representation of the species known to
American conchologists as U. radiatus, and which he says came from Virginia.
Chemnitz (vol. vi. t. 2, f. 7.) gives a representation of a shell very similar to it,
the locality of which is Malabar. The first name we find for it is in Gmelin,
Mya radiata, and this author refers to both figures in his description. Dillwyn re-

VOL. 111.—5 N

416 NEW GENUS AND SOME NEW SPECIES

[ Feaulea Say.
rarisulcata, Lam.
coarctata, Lam.
purpurascens, Lam.
rhombula Lam. var. 6b.
2. U. complanatust, Soland. MSS.¢ pariaiierse Tui.
| georgina*, Lam.
sulcidens, Lam.
caroliniana, Bose.
{ fluviatilis, Green.

fers to each of the above authorities, but thinks Lister’s figure is too doubtful to be
retained, as Solander had referred to it fora variety of Mytilus modiolus, in which,
however, he errs, for Lister’s figure is a good representation of a small specimen
of the radiatus of our waters. Lamarck, in his description of ‘*U. radiata,’ re-
fers to Lister and Gmelin, and also to the figure of Mr Say’s ochraceus. The last
is a distinct species. Several of these writers refer also to the figure in the Ency.
Meth. t. 248, f. 5, which is evidently copied from Chemnitz. Mr Barnes, in his
description, refers to Say’s U. ochraceus, Dillwyn’s Mya radiata, and Lamarck’s
U. radiata. Considerable difficulty presents itself in establishing the name of
this species, so well known among us by that of U. radiatus, in consequence of
the old writers using the same name for those from Virginia and Malabar, which,
I believe, when examined together, will be found specifically to differ. Should
this prove to be the fact, we must give to our shell the name which Lamarck has
described it under a second time, viz. ‘* U. virginiana,”’ giving it a masculine ter-
mination.

* Tt should be mentioned here that I was not aware that Mr Barnes had pro-
nounced the first six to be varieties of Say’s purpureus until after I had selected
the seven.

{ The celebrated Lister published his great work on conchology in 1685, and
at that early period he was in possession of several species of our fluviatile shells
procured from Virginia. The first he thus describes, ‘‘ musculus brevior, admo-
dum crassus, ex interna parte subroseus, cardine incisuris minutis exasperato,”’ t.
150, f. 5. Dillwyn describes this shell under the name of Mya complanata, and
refers to this figure. Beside the locality above, Solander gives Maryland and
New Jersey, and Humphreys Mississippi. The latter is most likely an error. Dr
Green supposed this shell, so well known to all our conchologists under Mr Say’s
name purpureus, to be the Mytilus fluviatilis described by Dillwyn from Gmelin,
and referred to Lister, t. 157, f. 12. I differ, however, in this opinion, 1. Be-
cause it is not described as being toothed. 2. Gmelin says, ‘‘ habitat in Europe
aquis dulcibus.’’ 3. The complanata answering, in description, better to our
shell, and being the first figured and described. It appears somewhat singular to
me, that the observant and able zoologist, Mr Say, had not been struck with the
similitude of our shell to Lister’s figure and description. ‘There is no species
more common in all our fresh waters, east of the Alleghany mountains, than
this, and nothing could be more likely than that it should be among the first to
be taken to Europe by the early voyagers to North America. In accordance,

OF THE FAMILY OF NAIADES. 417

- , f ovata, Lam.

3. U. ovatus, Say", peers Valenciennes.
luteola, Lam.
cariosa, Lam.

4. U. cariosus, Sayt, crassus (old), Say.

carinatus (rayed), Bar.
ellipticus (young), Bar.

5. U. nasutus, Say, rostrata, Valen.
Acer naviformis, Lam.
6. U. cylindricus, Say, Ht ea Valonk
7. U. subtentus, Say.
crassidens ? Lam.
peruvianus, Lam.
rariplicata, Lam.
8. U. plicatus, Le Sueur§, < undulatus, Bar.
3 crassus, Bar.
undulata, Valen.
| dombeyana, Valen.

therefore, with the rules of nomenclature, I have inserted the name of complana-
tus to the shell described by Mr Say under the name of purpureus.

* Dr Hildreth, in describing this species of Say, says, ‘‘ I think it a near rela-
tion of the gracilis ;’’ and, when describing the gracilis, he says, ‘* The contour
of the shell, independent of the wing, is much like that of the alaéus.” In the lat-
ter he is right, but in the former remark altogether wrong.

Donovan, Dillwyn, Maton and Racket, and some other British writers have
made use of thisname for a Unio resembling the pictorum. Ihave thought it bet-
ter, however, to retain Mr Say’s name for his species, which is totally different,
being satisfied that the British shell is only a variety of pictorum.

+ This is probably the only species yet known to be common both to the Wes-
tern and Atlantic waters.

{ Crassus is omitted in this catalogue, believing that several other species, and
those only because they were ponderous, have been described under this name.
Mr Say’s crassus (See Am. Conch. plate 1, fig. 8,) is evidently an old and ponde-
rous cariosus, and he considered the ‘‘ plicatus” as a variety. Mr Barnes’s eras-
sus is an old and thick peruvianus, as is most likely Lamarck’s crassidens. 'The
giganteus of Dr Mitchill’s collection is also a perwvianus, which occurs in some of
our western waters of a larger size and more ponderous than any species we
know of.

§ This species was first described by Say in the American Conchology asa va-

418 NEW GENUS AND SOME NEW SPECIES

( prelongus, Bar.
9. U. rectus, Lam.* ere hae
(recta, Valen.
10. U. torsust, Rafinesque.
11. U. mytiloides, Rafin. undatus, Bar.
12. U. metanever, Rafin. een Uae
13. U. scalenius, MRafin.
14. U. cornutus, _— Bar.f

riety of crassus. At the same time he mentioned that its discoverer, that excellent
naturalist Mr Le Sueur, suspected it to be a new species, and proposed, should
this prove to be the case, to call it ‘‘ plicata.’ We are, therefore, bound to
adopt his name on the claim of priority ; anda more descriptive one could not
be given to it.

* When Dr Hildreth described the ** prelongus,”’ it is evident he believed it to
be prelongus of Barnes, for he uses Barnes’s name without stating it to differ from
his, although the descriptions are not exactly the same. Barnes says, ‘t Naker,
purple of different shades,” and “ deep and splendid purple.”” (See Barnes’s Re-
clamation.) Hildreth says, “‘ Naker, white, and tinged with spots of green.”

The specimen of ‘recta,’ described by Lamarck, was “ white,”’ according to
his description. I have seen very many specimens of this species, some of which
are tinted with light purple or salmon about the cavity of the beaks and cardinal
tooth ; they are generally, however, of a pure white. The explanation of these
contradictory characters is this: The specimen in the collection of the New York
Lyceum, and the same is said of one in Dr Mitchill’s collection, both brought from
the upper lakes, is unusually full of colour, having almost the whole of the nacre of
a rose or delicate purple. It has more colour than any specimen I have seen.

} M. Rafinesque is entitled to a preference in this beautiful and extraordinary
species, possessing the most elevated recurved beaks of the whole genus. It was
generally known among us by the name of U. orbicularis, but not described. The
variety, not emarginate, can not be made a species, as the two pass into each other.
Dr Hildreth has recently described a shell, which I believe to be the torsus, in Sil-
liman’s Journal under the name of U. orbiculatus. He says, ‘‘ This shell is a va-
riety of the crassus.’’ Whose crassus? Mr Say’s, as mentioned before, is a pon-
derous cariosus; Mr Barnes’s, a peruvianus; and, if a variety of crassus, why
call it orbiculatus ?

{ This species is among the most interesting of the genus. It presents a much
greater variety than any other, and might be called a real proteus. The true

OF THE FAMILY OF NAIADES. 419

15. U. verrucosus, Bar. § verrucosa, Valen.
? tuberculosa, Valen.

16. U. tuberculatus, Bar.

17. U. gibbosus, Bar. mucronatus, Bar.

18. U. cuneatus*, Bar.

19. U. ventricosust}, Bar.

20. U. siliquoideus, Bar. inflatus, Bar.

21. U. triangularis, Bar.

cornutus has three or four distinct ‘* horns,’’ and the varieties gradually increase

in the number, and vary in the forms of those elevations until they are lost in two
ridges passing from the beaks to the posterior basal margin. It is exceedingly
interesting to trace these gradual changes of form; and to illustrate the fact of
the anomalous varieties being of the same species, I have arranged forty-three
specimens in my cabinet, no two of which are alike. Dr Hildreth has made a
species of one of these varieties, and calls it foliatus. It appears that Mr Barnes
and himself had seen only this specimen. I have had three or four in my posses-
sion for three years, and at first my impression was in favour of their being
new, but examining them with that excellent conchologist, Mr Stewart, we found
the line of impression, made by the mantle, did not run parallel with the deep
arcuation of the margin, and therefore concluded, at once, that the animal could
not conform to the shape of the shell, and consequently that the elongations of the
basal and posterior margins were unnatural. Dr H. says he is ** unable to deter-
mine whether it is a new variety, or only a “ lusus nature ;”’ and yet he makes a
new species of it!! Some of my varieties have the prolongation much more ex-
tended than the specimen described by Dr H. In one specimen the unnatural
prolongation is more than equal in extent to the natural size of the shell, designa-

ted by the impression of the mantle.

* We have been much in the habit of confounding this with the complanatus, and
considering it as the analogue inhabiting the western waters. It deserves, how-
ever, to be retained by Barnes’s name, for it possesses characters which the other
does not. It is posteriorly more angular, and the shell is subtriangular ; the com-
planatus is sub-rhomboidal and more carinate. One inhabits the western; the other
the Atlantic rivers. The cuneatus is always ponderous; the complanatus, I believe,
never. Mr B. says his species is never rayed ; in this he is mistaken, young and
fine specimens have dark broad rays.

} This is undoubtedly the species which we have known under the name of glo-

bosus (undescribed). Mr B. says “it is more capacious than any of the genus
hitherto described.”’ It resembles the ovatus, but is always more globose.

VOL. 111.—5 0

420 NEW GENUS AND SOME NEW SPECIES

22. U. parvus*, Bar.
23. U. esopus, Green.
24. U. calceolust, Lea.
25. U. lanceolatus, Lea.
26. U. donaciformis, Lea.
27. U. ellipsis, Lea.
28. U. irroratus, Lea.
29. U. lacrymosus, Lea,
30. U. ater, Lea.
31. U. rubiginosus, Lea.
32. U. heterodon, Lea.
33. U. sulcatus, Lea.
34. U. planulatus, Lea.
35. U. circulus, Lea.
36. U. multiradiatus, Lea.
37. U. occidens, Lea,
38. U. securis, Lea.

* This is rather the smallest species with which I am acquainted. Barnes says
it is ‘the smallest and most beautiful of all the genus yet discovered in America.”
In this he alludes to the nacre only, which is more pearly and more brilliant than
any species I haveseen. The exterior presents nothing peculiar but its concentric
waves on the beaks, and a slightly elevated rib passing from the beaks to the pos-
terior margin,

} Although I had three specimens of this shell in my possession when I deseri-
bed it, I felt apprehensive it was too closely allied to the Alasmodonta of Say to be
considered as an Unio; but asa lamellar plate really existed with an incipient
tooth, though small, on each valve, besides the large cardinal tooth, I determined
it to be the safest plan to class it with the Uniones. I have recently received larger
specimens in which this plate almost entirely disappears, while in younger speci-
mens it is more evident.

OF THE FAMILY OF NAIADES. 421

39. U. iris, Lea.
40. U. zig-zag, Lea.
41. U. patulus, Lea.

Conchologists have with great reason complained of the
extreme difficulty of identifying Lamarck’s species of the ge-
nus Unio. Mr Barnes says, “In most cases wherever M.
Lamarck can find a difference, though by his own account
‘nothing remarkable, he makes a different species ;” and Mr
Swainson declares that “one half the species which he has
enumerated” cannot be determined on account of the short
descriptions and want of figures. The truth of these remarks
I have felt severely whenever I have had occasion to consult
this author for the genus; and, with the hope of clearing the
path in a measure of those who may follow me, I propose to
give here the results of examinations of his species made at
different times with much care.

U. sinuata. This is the Mya margaritifera of Linneus
and other authors, and to which Barnes’s Alasmodonta arcu-
ata is the analogue. Mr B. was not aware, when he descri-
bed it, that it was similar. He has recently, in the reclama-
tion of his Uniones, resigned this species of Alasmodonta. If
Mr Say’s genus be admitted, we must of course call this type
of Lamarck’s Unio, 4lasmodonta margaritifera.

U. elongata. There can scarcely be a doubt but that this
is a young shell of the above species.

U. crassidens, It is evident on examination of our author’s
description of this species and its varieties, and the crassus of
Say and of Barnes, that all the ponderous varieties of our
Uniones were brought into these species, neither of which
can possibly stand. (See note, page 417.)

U. peruviana. This species embraces the plicata of Le
Sueur, the crassus and undulatus of Barnes, the giganteus of
Dr Mitchill’s collection, the rariplicata and crassidens of La-
marck, and the undulata and dombeyana of Valenciennes.

429 NEW GENUS AND SOME NEW SPECIES

As it was described previously by Le Sueur’s name “ pli-
cata,” this must take precedence. Its habitat, Peru, I think
very doubtful; it most probably came from the United States.
U. rariplicata. 'This is, no doubt, a variety of the above.
U. purpurata. The recta answers to this description in
every respect but the habitat. The author “believes” it
came from Africa. The shell most probably came from the
United States, in which case there could not be a doubt.
( The description of these is so imper-
ioe : i fect that I cannot identify either of them,
U. ligamentina, : 3
23 although they are all from this country,
U. obliqua, ihe aler : PN Ea
We hasan : and the same species most probably in
° our cabinets. I doubt if either of them
should be retained.

These are mere varieties of the com-

7. coarctata, planatus

U. purpurascens.

U. radiata. Our author gives the Mya radiata of Gmelin
and U. ochraceus of Say as synonymes to this species. It
cannot be both; for the ochraceus is a perfectly distinct spe-
cies from the JZ radiata, which, Chemnitz says, comes
from the rivers of Malabar. The radiatus described by
Barnes after Lamarck, and Say’s ochraceus are distinct spe-
cies, and I have no doubt the Mya radiata of Gmelin is
distinct from both. Mr Say’s figure, referred to by Mr
Barnes (pl. 2, fig. 8, Am. Conch.) as U. radiata, is undoubt-
edly an ochraceus. (See note on U. radiatus.)

U. brevialis. 'This shell is pictured by Crouch; it is thick,
and resembles the cireulus of the Ohio, but is larger, less
round and radiated. It comes from the Isle of France, and
is, no doubt, a distinct species.

U. rhombula,

U. rarisuleata,

Are all mere varieties of the com-

U. carinifera
fora, planatus.

U. georgina,
U. clava. I cannot identify this species. The descrip-
tion is too short. Its habitat is Lake Erie and Nova Sco-

OF THE FAMILY OF NAIADES. 493

tia, from which circumstance it is most probably in our cabi-
nets under another name.

U. recta. This is the same with Barnes’s prvlongus. The
recta being described first should be retained.

U. naviformis. 'This name cannot be retained, as Say had
previously described the shell under the name of cylindricus.

U. glabrata. 'The habitat of this species is the Ohio river.
The description is too imperfect to identify it, and as the au-
thor acknowledges it has “ nothing remarkable,” we may fairly
conclude it to be a variety of some one of the numerous spe-
cies described, a cariosus most probably.

U. nasuta. The author thinks this may be the nasutus of
Say, but the description answers much better to his own recta
or Barnes’s gibbosus, and is no doubt one of those. I do not
- believe the nasufus has ever been found in our western wa-
feEs*os

U. ovata is the ovatus of Say, and inhabits the western wa-
ters, not the Susquehanna and Mohawk, as mentioned by La-
marck. Maton and Rackett described a British shell under
this name, which I believe to be only a variety of pictorum.
Those sent me from England by this name were certainly
mere varieties of the pictorum.

U. rotundata. In most of our cabinets may be found a
beautiful shell, which we have thought to be of this species.
and have adopted the name. It does not, however, answer
to the description in some essential characters, and I have
therefore thought proper to describe the American shell, and
give itanewname. (See description of eirculus.) Lamarck
gives no habitat. Ours is from the Ohio.

U. littoralis is from the Seine, and is described by Drapar-
naud, who says it resembles the “U. margarififera,”. but is
much smaller.

U. semirugata. Description too short to identify it. Has
no habitat.

* Swainson says, ** The Unio nasuta, however, of Lamarck, I apprehend, will
be found different’’ from Unio nasutus of Say— Zool. Illus. Vol. f. pl. 57.
VOL. I11.—5 P

424 NEW GENUS AND SOME NEW SPECIES

U. nana. This species is said to inhabit Franche Comte.
I do not know if there be a specimen in this country.

U. alata is the well known alatus of Say, and is herein
made the type of a new genus, Symphynota.

U. delodonta. Description too short to identify it. Has
no habitat.

U. sulcidens. A variety of complanatus ; and is from the
Schuylkill, Pennsylvania.

U. rostrata. The specimens which I received from Eu-
rope with this name are only elongated varieties of pictorum.

V7. pictorum. This is a well known species, and described
by Linnezus and others as Mya pictorum.

U. batava. The specimens sent me of this species from
Europe appear to be only a variety of the pictorum. It is
more obtuse*.

U. corrugata. 'This species can not be identified with any
of ours. It comes from the coast of Coromandel, and is,
doubtless, a distinct and well characterised species.

U. nodulosa. The habitat of this species is Lake Cham-
plain, and although pictured in the Ency. Meth. I cannot
identify it, the drawing being evidently incorrect. Although
represented with a lamellar tooth, I should not be surprized
if it proved to be a young Mlasmodonta undulata of Say, as
it has the strong character on the beaks.

U. varicosa. I can only assimilate this with the Alasmo-
donta undulata of Say. Its habitat is the Schuylkill and
Lake Champlain.

U. granosa. This is a beautiful and distinct species. Ha-
bitat Guyana.

U. depressa. Habitat New Holland. The description is
very imperfect, but the species nevertheless distinct. It is a
very different shell from that called depressa by Rafinesque,
who does not seem to have known that the name was preoc-
cupied by Lamarck.

* The U. anas I believe to be a variety of pictorwm very similar to this. My
specimen is certainly such. The U. tumida, from the north of Europe, appears
to me to be only a large and thick pictorum. '

OF THE FAMILY OF NAIADES. 425

U. virginiana. This, doubtless, is the radiatus described
by Barnes. Habitat Virginia.

U. luteola is a variety of Say’s cariosus. Habitat Susque-
hanna and Mohawk.

U. marginalis. I have specimens of this species from
Bengal. It is well characterised, although it does not always
possess the marginal character as described by Lamarck and
represented in the Ency. Meth. pl. 247.

U. angusta. This I believe to be a variety of pictorum.
The figure referred to in Lister is certainly a pictorum, and
is generally quoted as such. Habitat unknown.

U. manca. 'This may be a distinct species, but I strongly
suspect it to be only a variety of pictorum. Habitat Bour-
gogne.

U. cariosa is the cariosus of Say.

U. spuria. 1 cannot identify this species with any of ours.
Habitat .....

U. australis. 'This, like the above, is not identified. Ha-
bitat New Holland.

U. anodontina. WHiabitat Virginia. We have no Unio of
this description in our waters. It is probably Anodonta un-
dulata of Say, which has sometimes small elevations some-
what similar to teeth*.

U. suborbiculata. I cannot identify this species.

In passing criticisms upon the species of the genus Unio of
this great naturalist, Ido not in the least wish to detract from
his great and merited fame. My object is expressly to en-
deavour to facilitate the study of this interesting genus, and
to remove, as far as I have it in my power, the confusion
which has crept into it. My observations I wish to pass
only for what they may prove to be worth.

* Since writing the above, I observe that Sowerby on the Lamarckian Naiades
(Zoolog. Journ. Vol. I. p. 54.) gives the ‘*.Anodon rugosus’’ of Swainson as
the synonyme of U. anodontina. It is well known to our conchologists that
Swainson’s rwgosus is the old shell of Say’s Anodonta undulata, which was de-
scribed from a young specimen, and has priority to the rugosus.

426 NEW GENUS AND SOME NEW SPECIES

1. Unto ATER. Plate VII. fig. 9.

Testa ovata, inequilaterali, transversa, ventricosissima; wmbonibus
elevatis ; natibus prominulis ; epidermide rugosa nigraque; umbonibus
elevatis; dentibus cardinalibus erectis, cristatis, lateralibus granulatis,
rectisque; margarita rosed.

Shell inequilateral, ovate, transverse, much inflated ; umbones elevated ;
beaks slightly prominent ; epidermis black and wrinkled ; cardinal teeth
erect and crestlike, lateral granulated and straight; nacre rose colour.

Hab. Mississippi below Natchez. 'T’. W. Robeson.

My Cabinet.

Cabinet of Prof. Vanuxem. Z
Diam. 2-6, Length 3, Breadth 4:5 inches.
Shell very ventricose ; margin ovate, wider behind, slightly
emarginate at base, and sometimes slightly truncate at poste-
rior margin; substance of the shell thick; beaks slightly pro-
jecting and decorticated ; ligament large; epidermis black or
blackish, and wrinkled transversely; cardinal teeth erect,
crestlike, and double in both valves; lateral tooth curved,
long, deeply divided and slightly serrate, the interior division
emerging from the cavity of the beak; posterior cicatrices
confiuent, anterior cicatrices very distinct ; dorsal. cicatrices
pass across the cavity of the beaks in a row*; cavity of the
shell great; nacre pink and iridescent in the posterior margin.

—

Remarks.—This shell is remarkable for the colour of its
epidermis and nacre. The perpendicular distance from the
cardinal tooth to the basal margin is very small, while that
from the posterior end of the lamellar tooth to the same mar-
gin is unusually great. It slightly approaches in form to
some varieties of the cariosus.

* Jn a former paper of this volume, (page 262) I described the attaching mus-
cles of the back of the animal, the impressions of which in the shell I propose to
call dorsal cicatrices.

P1.VU, vol.

ater

Unto

OF THE FAMILY OF NAIADES. 427

2. Unto Rupiernosus. Plate VIII. fig. 10.

Testa inequilaterali, transversd, postice sub-biangulari, antice rotun-
data; valvulis sub-crassis ; natibus prominentibus, recurvis, postice sub-
angulatis ; dente cardinali magno, laterali crasso; margarita salmonis
colore.

Shell inequilateral, transverse, sub-biangular behind and rounded be-
fore; valves somewhat thick; beaks prominent, recurved, sub-angulated
behind; cardinal tooth large; lateral tooth thick; nacre salmon co-
loured.

Hab. Ohio.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of the Academy of Natural Sciences.

Diam. 1-2, Length 2-1, Breadth 2-6 inches.

Shell somewhat ventricose ; substance of the shell some-
what thick; umbones slightly elevated; beaks recurved, sel-
dom decorticated, almost touching, whitish, possessing several
concentric undulations, which are lost along the umbonial
slope, which is carinate; a small curved elevated line passes
from the point of the beaks to the margin above the posterior
margin; ligament rather large passing from the points of the
beaks; dorsal margin oblique; posterior dorsal margin cari-
nate and slightly emarginate; posterior margin angular: pos-
terior basal margin very slightly curved; basal, anterior and
anterior dorsal and basal margins rounded; epidermis colour
of rust, sometimes salmon yellow, slightly wrinkled and show-
ing the marks of growth; rays in young specimens percepti-
ble; cardinal tooth suleate, broad and not elevated, often
single in both valves; the tooth in the left valve closing in a
cavity which sinks almost into the cavity of the beaks of the
right valve; lateral teeth rather thick, elevated, straight, ge-
nerally double in both valves; in the left valve the upper
division is less elevated and shorter; anterior and posterior
cicatrices both distinct; the smaller posterior cicatrix is situ-

VOL. I1t.—5 Q

428 NEW GENUS AND SOME NEW SPECIES

ated against the side of the lamellar tooth, near its termination ;
the anterior adductor muscle makes a cicatrix also against the
end of the cardinal tooth; dorsal cicatrices under the cardinal
tooth perceptible; cavity of the beaks deep and rounded ; na-
cre always more or less salmon colour; slightly iridescent at
posterior margin; whitish on the margin near the adductor
muscles.

Remarks.—This is a very distinct species. In its general
form it approaches nearest to the securis, which, however, is
always white in the nacre, and peculiarly rayed. It is pecu-
liar in its reddish brown epidermis, which colour is caused
by the salmon nacre showing through it. The character of
the cardinal tooth is very peculiar, having a tendency to be
single in both valves, while the lamellar tooth is quite equally
disposed to be double. All the specimens which I have seen
are salmon colour in the nacre. If this should prove univer-
sally so, it is the only species which we know to be con-
stantly of that colour.

3. Unto HeTeropon. Plate VIII. fig. 11.

Testa rhomboido-ovata, inequilaterali, ventricosa ; valvulis tenuibus ;
dentibus cardinalibus compressis, latis ; dentibus lateralibus sub-curva-
tis, dente laterali valvule dextre, duplici ; natibus prominentibus ; liga-
mento sub-brevi; margarita alba.

Shell rhomboidal-ovate, inequilateral, ventricose; valves thin; cardi-
nal teeth compressed, wide; lateral teeth slightly curved, the double
tooth in the right valve; beaks prominent; ligament rather short; nacre
white.

Hab. Schuylkill and Derby Creek, Pa.
My Cabinet.
Cabinet of Mr Mason.
Cabinet of Prof. Vanuxem.
Cabinet of Dr Griffith.

» VHT vel

Unto rubiginasus . Onto heteradon Unto sulcatus

OF THE FAMILY OF NAIADES. 429

Cabinet of the Academy of Natural Sciences.

Cabinet of Mr Hyde.

Cabinet of Mr Phillips.

Cabinet of Mr Conrad.
Diam. °5, Length -9, Breadth 1-5 inches.

Shell rhomboidal-ovate, inequilateral, ventricose ; substance

of the shell thin; beaks prominent, subcarinate posteriorly,
eroded, undulated ; ligament rather short; epidermis green-
ish brown, with oblique obscure rays, wrinkled ; dorsal mar-
gin rectilinear; posterior dorsal margin obtusely angular ;
posterior margin acutely angular; basal margin slightly curv-
ed; anterior, anterior basal and dorsal margins rounded;
cardinal tooth in left valve compressed, wide, reaching be-
yond the cavity of the beaks, double cleft; in right valve one
elevated recurved tooth, which clasps the side of the opposing
one; lateral tooth curved, short in left valve, and long in the
right, in which it is double; anterior cicatrices confluent, as
are also the posterior; dorsal cicatrices situated on the under
part of the cardinal tooth, scarcely perceptible ; cavity of the
beaks large ; nacre white.

Remarks.—This remarkable species was first observed by
Mr Mason and Mr Hyde. To the kindness of the for-
mer I am indebted for the use of the fine large specimen
figured. It is very curious in the whole apparatus of the
hinge, the teeth of which resemble in some measure the
Symphynota compressa, herein described. From the ante-
rior end of the cardinal tooth to the posterior end of the late-
ral, the distance is the same in both valves, but in the left
valve the cardinal tooth is longest, while in the right valve
the lateral tooth is longest. The peculiar character of this
shell is in the double lateral tooth being in the right valve,
in which it differs from all the species yet described. It most
resembles in general form the Aasmodonta* marginata of

* Mr Say published his description of the genus Alasmodonta in the Journal of
the Academy of Natural Sciences of Philadelphia, 1818, without knowing, it is to

430 NEW GENUS AND SOME NEW SPECIES

Say; and some of the younger and more ventricose specimens
assume the appearance of the U. triangularis.

oe

4. Unio Sutcarus. Plate VIII. fig. 12.

Testa sub-elliptica, inequilaterali, ventricosd, sub-emarginatd ; valvu-
lis crassis ; natibus fere terminalibus ; dentibus cardinalibus lateralibus-
que magnis, et duplicibus in valvulis ambabus ; margarita purpurea,

Shell sub-elliptical, inequilateral, ventricose, slightly emarginate ;
valves thick; beaks nearly terminal ; cardinal and lateral teeth large, and
double in both valves; nacre purple.

Hab. Ohio. 'T. G. Lea.
My Cabinet.
Cabinet of 'T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.
Diam. 1:3, Length 1-7. Breadth 2-3 inches.
Shell very thick, ventricose, inequilateral, obliquely longi-
tudinal; margin sub-elliptical, with an emargination of poste-
rior basal margin, caused by a broad furrow running from the
beaks to this part of the margin; substance of the shell thick
and ponderous; beaks thick and projecting beyond the mar-
gin, nearly terminal, decorticated ; ligament partly concealed
by the beaks; epidermis olive-brown, wrinkled, with nume-
rous fine hair like lines, which are slightly undulated, passing
from the beaks to the margin; these lines are obsolete in the
anterior part of the shell, and crowded in the furrow, over
the umbonial slope they are proximate ; cardinal tooth eleva-
ted, conico-triangular, that in left valve deeply divided ; late-
ral tooth long, thick, and slightly curved, direction nearly

be presumed, that the Mya margaritifera of Linnzus was in 1817 erected into a
new genus by Schumacher, under the name of Margaritana. If the absence of the
lateral tooth be sufficient to establish the genus, we must necessarily call it by
the Danish naturalist’s name.

PL. IX Vol.3.

hg
YL Mie

Lf
i Ni
qi
i Hi Me

Tnio planulatus Onto circulus,

Trio multiradiatus

Drawn KEng‘d by L Drayton

OF THE FAMILY OF NAIADES. 431

same as cardinal tooth ; posterior cicatrices distinct, the smaller
one being placed immediately over the large one, and against
the lateral tooth; anterior cicatrices distinct; dorsal cica-
trices situated on the under part of the cardinal tooth, very
perceptible ; cavity of the beaks small; nacre flesh-red, vary-
ing from this to nearly white ; iridescent in the posterior mar-
gin.

Remarks.—This is variety a of U. ellipsis, described in a
former paper, and approaches it closely. Having seen seve-
ral specimens since that description was made, my doubts
have been satisfied, and I now consider it a new species. It
differs from the ellipsis in having the furrow, in being gene-
rally covered with fine hair-like rays, and in being always
more or less flesh-red inside. I have two specimens of this
species which present a singular formation of the posterior
basal margin, which is dentate, the points interlocking and
almost hooked. The elevation anterior to the furrow com-
mences to swell one-third of the distance from the margin
to the beaks, increases as it approaches the margin, and as-
sumes this dentation, which being successive as the shell
increases displays lamine of these dentations in the epider-
mis. In the interior this part of the shell has the appearance
of having been gouged out. It is exceedingly curious, being
the only specimen of fluviatile shells I have seen with a mar-
gin approaching to a dentate appearance.

5. Unto Pranutarus. Plate IX. fig. 13.

Testa inequilaterali, ovato-ellipticd, transversa; complanata per wm-
bones a natibus usque ad marginem inferiorem, maculis quadratis radi-
atim pictd ; natibus prominulis ; dente cardinali parvo, laterali magno,
crasso, curvato; margarita sub-ceruleo-alba.

Shell inequilateral, ovate-elliptical, transverse, flattened across the
umbones from the beaks to the basal margin, marked with square spots in
form of rays; valves thick; beaks slightly prominent; cardinal tooth
small; lateral tooth large, thick and curved ; nacre bluish white.

VOL. 111.—5 R

432 NEW GENUS AND SOME NEW SPECIES

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.

Diam. °8, Length 1:3, Breadth 2-2 inches.

Shell ovate-elliptical, remarkably flattened over the um-
bones from the beak to the basal margin, which frequently
causes the greatest diameter to be near to the anterior margin;
substance of the shell thick; beaks slightly prominent and de-
corticated ; ligament deeply seated, scarcely appearing above
the margin of the shell; epidermis wrinkled, yellowish brown,
with transversely interrupted rays passing from the beaks in
a slight curve to the margin along the umbonial slope; these
rays are hair like, undulated, and interrupted; cardinal
teeth very small and lobed; lateral tooth remarkably thick
and situated on a large massive plate; curve very slight and
directed much over the cardinal tooth, somewhat rough, up-
per division smaller than the lower; anterior and_ posterior
cicatrices both distinct; the smaller posterior cicatrix is situ-
ated against the end of the plate at the point of the divi-
sion of the tooth; dorsal cicatrices situated on the under part
of the cardinal tooth, perceptible; cavity of the shell very
small and irregularly waved; an indistinct depressed line
may always be seen to pass from the great posterior cicatrix
along the base of the lateral tooth into the cavity of the beaks ;
nacre white.

Remarks.—This shell is peculiar in the massive plate on
which is situated its short and thick lateral tooth, as well as
in the very small size of its cardinal tooth. It has scarcely
any cavity under the beaks, the shell being very thick. Its
epidermal rays, in perfect specimens, are very unusual to this
genus; in old specimens they are almost or quite obsolete.
It is remarkable also in its flat umbones. It resembles most
in form the gibbosus of Barnes, but is less rostrated and more

OF THE FAMILY OF NAIYADES. 433

thick. The gibbosus is seldom if ever perfectly white; all
the specimens I have seen of this are perfectly so.

6. Unto Circunus. Plate IX. fig. 14.

Testa circulari, ventricosd, sub-e@quilaterali; valvulis crassis ; natibus
prominulis; dentibus cardinalibus lateralibusque magnis; ligamento
brevi crassoque ; margarita alba et wridescente. r

Shell circular, ventricose, nearly equilateral; valves thick; beaks
slightly elevated; cardinal and lateral teeth large; ligament, short and
thick ; nacre pearly white and iridescent.

Ohio at Cincinnati. T. G. Lea.
Hab. ~ Monongahela at Pittsburg. 'T. Bakewell.
Tennessee at Nashville. Prof. Vanuxem.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of Dr Griffith.
Cabinet of W. Hyde.
Cabinet of W. Mason.
Cabinet of J. Phillips.
Cabinet of the Academy of Natural Sciences,
Cabinet of Peale’s Museum.

&e.
Unio rotundata 2? Lamarck.
Diam. 1, Length 1:5, Breadth 1:5 inches.

Shell round; posterior basal margin sometimes very slightly
emarginate, very ventricose, transversely wrinkled, nearly
equilateral ; substance of the shell thick; beaks elevated, me-
dial, and somewhat recurved; epidermis finely wrinkled,
shining, satin-like, anterior to the umbonial slope dark brown,
posterior light yellow brown; cardinal teeth oblique, thick,
and disposed to be treble in both valves; lateral teeth short
and thick, disposed to be double in right valve as well as left ;

434 NEW GENUS AND SOME NEW SPECIES

Anterior cicatrices distinct; posterior cicatrices also distinct ;
the smaller one being placed against the termination of the
lateral tooth; dorsal cicatrices situated on the under part of
the cardinal tooth, very perceptible ; cavity of the beaks deep
and sub-angular; nacre white, pearly, and iridescent, rarely
tinted with rose in the centre.

Remarks.—This beautiful little shell is generally an inch
long, rarely two. It is common in our cabinets, and has
been considered the “rotundata” of Lamarck. Iam induced,
however, to think it different from our shell, as_ the circulus
never possesses the fold mentioned in that eminent concholo-
gist’s very short description. ‘The two colours disposed in so
peculiar a manner in the epidermis are not mentioned by —
him. It differs also greatly in size. I have seen some hun-
dreds, the largest of which was two inches in breadth. The
“rolundata’ is 78 millimetres; and its habitat is unknown.

The margin of the circulus is more perfectly round than
any other species; it is sometimes disposed to be subangular
posteriorly. The division of the colour on the umbonial
slope is very peculiar. When the posterior slope is looked
on, this view of the shell is heart shaped, and the dark brown
colour is seen entirely to surround the light yellow brown.
The epidermis is more satin-like than any other species, and
the teeth are peculiarly disposed to be double. In form it
approaches the “¢orsa” more closely than any other species.

7. Unto Mutri-rapiatus. Plate IX. fig. 15.

Testa ellipticd, inequilaterali, ventricosa, multi-radiatd ; valvulis te-
nuibus ; natibus prominulis ; dentibus cardinalibus erectis, et in valvu-
lis ambabus duplicibus ; lateralibus lamelliformibus et abruptis ; mar-
garita ceruleo-alba.

Shell elliptical, inequilateral, ventricose, much rayed; valves thin ;
beaks rather prominent; cardinal teeth erect and double in both valves ;
lateral teeth Jamelliform and abrupt; nacre bluish white.

PIs Vols.

lo

Unto occtdens,

Drawn &Eng'@ by ZLrayton.

OF THE FAMILY OF NATIADES. 435

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.

Diam. °8, Length 1.3, Breadth 2 inches.

Shell elliptical, inequilateral, ventricose ; substance of. the
shell thin, the rays being very visible through the nacre;
beaks prominent and slightly undulated ; epidermis bright
olive yellow, with numerous green rays passing from the
beaks to every part of the margin; slightly wrinkled, smooth
and glossy ; cardinal tooth double in both valves and deeply
cleft; lateral tooth lamelliform, nearly straight, higher near
the termination, termination abrupt; anterior cicatrices dis-
tinct ; posterior cicatrices confluent; dorsal cicatrices situated
on the under part of the cardinal tooth, and within the margin
of the cavity of the beaks; cavity of the beaks large and round-
ed; nacre pearly white and iridescent, thin, showing the rays
very distinctly through it, and presenting a wide margin.

Remarks.—This beautiful shell resembles most the young
cariosus of the Ohio and other western waters. It. differs,
however, in being much less ponderous, possessing more mi-
nute rays, being rather more ventricose, having 1 more elevated
teeth and more prominent beaks.

8. Unto Occipens. Plate X. fig. 16.

Testi sub-elliptica, inequilaterali, transversd, ventricosé ; valvulis
crassis ; natibus sub-undulatis, raro decorticatis ; ligamento sub-brevi
crassoque; dentibus elevatis ; margarita alba.

Shell inequilateral, sub-elliptical, transverse, ventricose ; valves thick ;
beaks slightly undulated, rarely decorticated ; ligament rather short and
thick; teeth elevated ; nacre white.

Hab. Ohio. T. G. Lea.
My Cabinet.

VOL. 111.—5 s

436 NEW GENUS AND SOME NEW SPECIES

Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.

Cabinet of Peale’s Museum.
Diam. 1:6, Length 2:3, Breadth 3:4 inches.
Shell ovate, inequilateral, sub-elliptical, transverse, very
ventricose ; substance of the shell somewhat thick; beaks
large, prominent, rounded, approaching, slightly undulated,
rarely decorticated; ligament short and thick; epidermis
slightly wrinkled, shining, olive yellow, with green rays pas-
sing obliquely from the beaks to the margin, most numerous
on the posterior slope; cardinal teeth double and very promi-
nent in both valves; in the left valve the cleft is deep and
both prongs rake much, the outer most elevated ; in the right
valve the cleft is also deep, and the inner prong is broad, flat,
curved, and most elevated ; lateral teeth short and very lamel-
liform, the termination declining rather suddenly; anterior
cicatrices generally distinct; posterior cicatrices confluent;
dorsal cicatrices very perceptible, the line commencing with
quite a large one on the under side of the callus between
the lateral and cardinal teeth, and terminating at the outer
part of the base of the cardinal tooth; marginal cicatrix very
perceptible; cavity of the beaks deep, large and rounded ;

nacre milk white, rarely iridescent.

Remarks.—The specimen figured is the finest I have ever
seen of this species, and, taking it altogether, perhaps of any
other of the genus. The raysare very remarkably fine, and the
nacre is purer and whiter than the finest porcelain. It is very
frequently, however, found with few or no rays, and the na-
cre, though milk-white and pure generally, is not always so.
The double, deeply cleft, cardinal tooth of both valves, and
the raking position of that of the left valve are peculiar to the
species possessing this general form, which includes the ova-
tus and ventricosus. It seems to form the link between these
two. It differs from the ovafus in not possessing the flat

PL_XI Vol.3

Onio securis

Unita iris Symphynota tenuissima,

OF THE FAMILY OF NAIADES. 437

posterior slope, and from the ventricosus in not being globose
over the umbones; and of course is much less in diameter.
The quite large impression of the mantle under the callus,
between the lateral and cardinal teeth, is very remarkable in
these three species.

9. Unio Securis. Plate XI. fig. 17.

Testa subtriangulart, inequilaterali, per umbones valde complanata ;
valvulis crassis ; natibus elevatis, recurvatis, compressissimisque ; dente
cardinali magno, laterali crasso; ligamento breviusculo, crassoque ;
margarita alba et iridescente.

Shell sub-triangular, inequilateral, flattened over the umbones; valves
thick ; beaks elevated, recurved, much compressed ; cardinal tooth large ;
lateral tooth thick; ligament rather short and thick; nacre pearly white
and iridescent.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of the Academy of Natural Sciences.
Unio depressa of Rafinesque.
Diam. -9, Length 1:5, Breadth 1-9 inches.
Shell sub-triangular, transversely wrinkled, inequilateral,
much flattened over the umbones; substance of the shell
thick, often ponderous; beaks elevated, much compressed,
recurved ; dorsal margin angular; posterior dorsal margin ob-
lique; posterior margin angular; basal and posterior basal
margin curved; anterior and anterior basal and dorsal mar-
gins round; posterior slope flattened, this view presents the
shell as a long ellipsis; epidermis olive-yellow passing into
olive-brown, shining and transversely wrinkled; rays formed
by small spots, alternately darker and lighter than the gene-
ral colour of the epidermis, which cause the rays to look like
a minute chain, these rays are from one to two eighths of an
inch apart, and extend over the whole disk, the spaces be-

438 NEW GENUS AND SOME NEW SPECIES

tween are supplied with numerous hair-like lines, the whole
passing in a curve from ‘the beak to the margin; cardinal
tooth large, irregularly cleft and suleated ; lateral tooth rather
short and thick, in the right valve disposed to be double; an-
terior cicatrices distinct ; posterior cicatrices also distinct, the
small one being placed against the termination of the lateral
tooth; dorsal cicatrices situated on the under side of the car-
dinal tooth; cavity of the beaks shallow and rounded ; cavity
of the disk small; nacre pearly white and iridescent.

Remarks.—Mr Rafinesque first observed this singular and
interesting species. He found a single specimen near Evam-
ville, Indiana, and described it under the name of U. de-
pressa, which name being preoccupied by Lamarck, I have
considered it incumbent on me to give ita new name. Many
specimens have come under my inspection, and the shell be-
ing a very remarkable one, I am induced, in consequence of
Mr Rafinesque’s short description and imperfect figure, to
give a more full description and a correct figure. It is alto-
gether peculiar in its rays and its very compressed beaks; no
species is so flat over the umbones, and no other species pre-
sents, when the posterior slope is held towards the observer,
a long ellipsis, the widest part of which is about the centre.
In consequence of the beaks being so very much compressed,
the junior, when not more than an inch long, is exceed-
ingly flat, and the cavity proportionally small. When the
shell increases beyond this it seems to become suddenly thick,
and its form becomes more rounded towards the margins,
consequently the adult is very different in form from the
junior, which might easily be mistaken for another species.
It is more generally gaping at the anterior margin than the
other species. It assimilates closely to the planulatus (de-
- seribed in this paper), but differs in the rays, the much
compressed beaks, and being more hatchet shape. In the
last character it resembles somewhat the rubiginosus descri-
bed in this paper. It sometimes occurs twice the size of the
one represented here.

PL.X11.vol.3

DallUelus.

ZAG

Z2G/-

Unto

Symphynota compress td

OF THE FAMILY OF NAIADES. 439

10. Unio Irts. Plate XI. fig. 18.

Testa angusto-elliptica, inequilaterali, sub-ventricosa; valvulis tenu-
bus ; natibus prominulis ; dente cardinali in valvula sinistra, duplici, in
dextra sub-bifido, parvo, erecto ; dentibus lateralibus longis tenuibusque ;
margarita sub-ceruleo-alba.

Shell narrow-elliptical, inequilateral, slightly ventricose ; valves thin,
beaks slightly prominent; cardinal teeth double in the left valve, sub-
bifid in the right, small, erect ; lateral teeth long and thin; nacre bluish
white.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.

Diam. °5, Length °8, Breadth 1-6 inches.

Shell long-elliptical, inequilateral, slightly ventricose ; sub-
stance of the shell thin, showing the rays through it, rather
more dense before than behind; beaks slightly prominent,
approaching, crowned with double concentric undulations
when they are not decorticated; ligament rather long and
thin; epidermis yellowish green, transversely wrinkled, mark-
ed with many oblique diverging rays passing from the beaks to
the margin; cardinal teeth double in both valves, small, erect,
and sharp; lateral teeth long, bladed, slightly curved and situ-
ated on the edge of the margin in contact with the ligament ;
anterior cicatrices distinct ; posterior cicatrices confluent and
scarcely perceptible; dorsal cicatrices within the cavity of the
beaks, the largest on the under part of the callus; nacre very
thin, milk white anteriorly, bluish white and iridescent pos-
teriorly.

Remarks.—This species most resembles the calceolus. It
differs, however, entirely in the teeth, which are distinct and
well defined. The calceolus approaches closely to the genus
Alasmodonta of Say. 'This is less ventricose and possesses
more rays.

VOL. UL.—5 T

440 NEW GENUS AND SOME NEW SPECIES

il. Unto Zie-zac. Plate XII. fig. 19.

Testa ovata, inequilaterali, ventricosa ; valvulis sub-crassis ; dentibus
cardinalibus magnis, erectis ; lateralibus curvatis ; natibus prominulis ;
radits ex lineis angulatis compositis ; ligamento brevi crassoque ; marga-
rita alba.

Shell ovate, inequilateral, ventricose; valves rather thick; cardinal
teeth large, erect; lateral teeth curved; beaks rather prominent; rays
composed of zig-zag lines ; ligament short and thick ; nacre pearly white.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.
Cabinet of Peale’s Museum.
Diam. ‘6, Length -9, Breadth 1-5 inches.
Shell ovate, inequilateral, ventricose ; substance of the shell
thick; beaks rather prominent, subcarinate posteriorly, gene-
rally eroded; ligament short and thick; epidermis yellow in
ground, but traversed by oblique green rays, which give it
sometimes a dark hue; these rays pass from the beaks to the
margin over,the whole disk, and are formed by zig-zag lines,
which in some specimens are joined so closely as to become
confluent; on the posterior slope are irregular lines converging
below the ligament; cardinal teeth large, deeply divided in
the left valve; lateral teeth slightly curved; anterior cica-
trices distinct, as are also the posterior, the smaller of which
is placed against the side of the lateral tooth at its termina-
tion; dorsal cicatrices situated along the base of the cardinal
tooth within the cavity of the beaks; cavity of the beaks
shallow; nacre pearly white and iridescent.

Remarks.—This beautiful little shell is about the size of
Barnes’s parvus. It is however entirely distinct from it. It
is much heavier, more ovate, and radiated ; has no concentric
undulations at the beaks like the parvus, which character Mr

OF THE FAMILY OF NAIADES. 441

Barnes does not mention, and is yellowish, not brownish.
This and the donaciformis are all I know which possess the
zig-zag markings, and they most resemble each other.

12, Unio Parunus. Plate XII. fig. 20.

Testa ovata, compressa, cuneiformi, inequilaterali, obliqua, trans-
versa ; umbonibus compressis ; valvulis sub-crassis ; natibus swb-termi-
nalibus ; dente cardinali parvo ; laterali longo et sub-curvato ; margarita
alba.

Shell ovate, compressed, wedge-shaped, inequilateral, oblique, trans-
verse, compressed on the umbones ; valves rather thick; beaks nearly
terminal ; cardinal tooth small; lateral tooth long and slightly curved ;
nacre pearly white.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.

Diam. °8, Length 1-4, Breadth 2-3 inches.
Shell compressed, wedge-shaped, ovate, broad and flat ; sub-
stance of the shell thick anteriorly and thin posteriorly, show-
ing the rays through it; beaks nearly terminal, slightly pro-
minent, approaching, and when perfect possessing slight
concentric undulations, generally decorticated ; ligament not
large, passing from the point of the beaks ; epidermis yellow-
ish brown, transversely wrinkled, marked with more or less
broad interrupted rays, apparently formed of fasciculi of hair-
like lines; cardinal tooth short, and but slightly elevated, in
the left valve double and deeply cleft, in the right valve
emerging from a pit; lateral tooth long and slightly curved ;
posterior cicatrices as well as anterior cicatrices distinct; the
smaller posterior cicatrix situated against the lateral tooth at
its termination; dorsal cicatrices on the under part of the car-
-dinal tooth ; cavity of the beaks not deep but rounded ; nacre
thick and milk white anteriorly, thin and iridescent poste-

riorly.

442 NEW GENUS AND SOME NEW SPECIES

Remarks.—This species approaches closely to the scalenia
of Rafinesque; its rays are of the same description, and the
general form is the same. It is, however, more flattened, has
much less elevated beaks, and its diameter is always much less.
Its beaks are generally but little decorticated, and not recurv-
ed; the scalenia is generally much recurved and decorticated.

|

GENUS SYMPHYNOTA.

Testa fluviatili, bivalvi ; valvulis superné connatis.
Shell fluviatile, bivalve ; valves connate at the dorsal margin.

Animal same as that of Unio. ‘

Remarks.—Objections will most likely be made to the in-
troduction of a new genus into a family acknowledged already
to be in great confusion, and presenting many and various
difficulties. 'The formation of the genus Symphynota, it is
hoped, will rather be conducive to a diminution of that diffi-
culty, by a division which all must acknowledge to be as na-
tural as any of those of the family. The distinctive charac-
teristic of this genus is the testaceous connection of the two
valves of the shell above the hinge. I therefore remove from
the existing genera all the connate shells without regard to
the forms of their teeth, believing, that should this family be
hereafter remodelled, it will present only two natural genera ;
one having a testaceous connection of the valves, the other
dispossessed of it. The difficulties attending the adopted ge-
nera of the Naiades, viz. Unio of Bruguiére, Hyria, Ana-
donta, Iridina, Castalia* of Lamarck, Dipsas of Leach, and

* This genus was placed by Lamarck in the family Trigonea, certainly with
no propriety. It has been placed by Sowerby and Latreille among the Navades,

OF THE FAMILY OF NAIADES. 445

Alasmodonta of Say, have been mentioned by two eminent
English conchologists, W. Swainson and G. B. Sowerby, as
well as in America by P. H. Nicklin. Mr Sowerby (Zool.
Journ. Vol. I. p. 55.) has reunited them under the name of
Unio, of which he makes two great divisions: 1. Without
teeth. 2. With teeth; and these are each subdivided into
“winged” and “not winged ;” which are again divided into
-the various forms of teeth, or the “hinge line.” ‘The evident
objection to this arrangement is the difficulty of deciding
upon the passage from the “not winged” to the “ winged.”
Thus we do not find the Anodonta trapezialis and Anodonta
glauca, which Lamarck describes as “ compresso-alata,’ men-
tioned among the “ winged,” while we have “nodon alatus
of Swainson and Lamarck,” which is not described in the
“Hist. Nat. des Animaux sans Vertebres*.”

It is evident that the apparatus for depositing the calca-
reous and epidermal matter on the elevated and connected
wing must be different from that of the inhabitant of free
valves, to which it has been denied by nature.

Lamarck and Barnes both mention in their description of
the U. alatus of Say, that M. Le Sueur thought this shell
should constitute a new genus. Since that time so many
connate shells have come to my notice, that I feel satisfied the
science of conchology will be subserved by the institution of
this natural genus, which will embrace, in all probability,
several others, viz. Hyria of Lamarck, Dipsas of Leach, and
Cristaria, Prisodon, and Paxyodon of Schumacher, all of
which, when they shall be found perfect, will most probably
turn out to be connate shells. Lamarck suspected his Hyria
to be connate, like the U. alatus ; for when describing that spe-
cies, he says, “ Nos Hyries auraient-elles une pareille réunion

and here must be considered as a species of Unio, and not a genus. The ob-
servant M. De Blainyille has placed Castalia and Hyria among the Uniones, and
Tridina and Dipsas among the Anadonte. Castalia ambigua is undoubtedly a
fluviatile shell, and approaches most closely to the U. triangularis. The teeth
are those of the Unio, and it differs only in its longitudinal furrows from the gene-
ral characters of the Unio.

* Say describes his An. gibbosa as being alated.

VOL. 111.—5 U

444 NEW GENUS AND SOME NEW SPECIES

i la caréne de leur corselet?” Indeed the fact can scarcely be
doubted.

SPECIES.

1. SympnynotTa Layissima. Plate XIII. fig. 23.

Testa ovato-triangulari, inequilaterali, transversim rugosa, sub-ven-
tricosd ; valvulis tenuissimis, superne bi-alatis, ante et post nates conna-
tisque; dentibus cardinalibus et lateralibus lineam curvatam facienti-
bus; natibus prominulis; ligamento celato; margarita purpurea et
iridescente.

Shell triangular-ovate, inequilateral, transversely wrinkled, sub-ven-
tricose; valves very thin, elevated into two wings, connate anteriorly and
posteriorly to the beaks; cardinal and lateral teeth form a curve line ;
beaks scarcely prominent ; ligament concealed ; nacre purple and irides-
cent.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.

Cabinet of P. H. Nicklin.
Diam. 1-4 inch. Length from beaks to base, 2-4 inches.
Breadth 4-5 inches.
Length from the top of the wing to base, 3-1 inches.

Shell sub-triangular-ovate, inequilateral, sub-ventricose,
transversely and very finely wrinkled, shinmg; substance of
the shell thin, but compact; valves elevated into two wings,
neither of them very high, the posterior one larger than the
anterior, both connate; beaks scarcely prominent, termina-
tion pointed, and when not decorticated exhibit two or three
very minute elevations, almost requiring a microscope to dis-
cover them; the purple nacre shows through the epidermis
here, and gives the tips that colour; ligament concealed in the
wing ; sinus subquadrate; epidermis thin and purple brown;
young specimens sometimes possess obscure brown rays; car-
dinal tooth lamelliform, single in the left valve and disposed to

PLXIL vol 3,

Symphynota leavesstma

PL.XIV Vol.3.

Symphynota bt-alata:

Drawn & Eng'd by LDrayton

OF THE FAMILY OF NAIADES. 445

be double in the right; lateral tooth lamelliform and double
in the left valve only, the two teeth form one continuous
curve line, somewhat abrupt at both terminations, more so
at the anterior one; anterior cicatrices distinct; posterior cica-
trices confluent; dorsal cicatrices very perceptible. Cavity
of the beaks wide and very shallow; nacre purple and irides-
cent.

Remarks.—This beautiful shell most resembles the Sym-
phynota alata in its general form, but its posterior wing is less
elevated. The colour of its nacre is the same. It differs
entirely, however, in the cardinal tooth, and in possessing the
anterior connate wing. A metallic sound is produced by
dropping one valve into the other, which is very remarka-
ble, and is caused by the density of the calcareous matter of
the nacre, which is very thin. The epidermis is exceedingly
smooth and glossy.

2. SympnynoTa Br-avata. Plate XIV. fig. 24.

Testa ovato-triangulari, inequilaterali, transversim rugosa, sub-ven-
tricosa ; margine dorsali bi-alata ; valvulis tenwibus, ante et post nates
connatis ; natibus et ale posterioris basi apiceque undulatis ; natibus
haud prominentibus ; dente lamelliformi unico in valvuld utraque; liga-
mento celato ; margarita tenui et iridescente.

Shell triangular-ovate, inequilateral, transversely wrinkled, sub-ven-
tricose ; dorsal margin raised into two wings; valves thin, connate before
and behind the beaks; beaks and the base and summit of the posterior
wing undulated; beaks not prominent; one lamelliform curved tooth in
each valve ; ligament concealed; nacre thin, pearly, and iridescent.

Hab. .... fresh waters of the south of Asia? Brought
from Canton by Captain Barr.
My Cabinet.
Cabinet of Mr Pierpoint.
Cabinet of Mr Hyde.
Cabinet of Mr Phillips.

446 NEW GENUS AND SOME NEW SPECIES

Diam. 1 inch. Length from the beaks to the base, 2 inches.
Breadth 3:6 inches.
Length from the top of wing to base, 3-4 inches.

Shell triangular-ovate, inequilateral, subventricose, trans-
versely and finely wrinkled, shining; substance of the shell
thin, showing the rays through it; valves elevated into a broad
high wing posterior, and a small one, anterior to the beaks,
and connate in both; beautifully undulated at the base and
top, of the posterior wing; undulations of the base commenc-
ing at the point of the beaks, pass on the outside of the tooth
to the margin in a slightly curved line, each successive wave
increasing in size and cutting the wrinkles of the epidermis
obliquely; those of the top of the wing, when it is perfect, are
about the same in number, but less elevated, and closer toge-
ther; they cut the wrinkles at about the same angle; beaks
not prominent, crowned with about six elliptical concentric
undulations; ligament concealed in the wing; sinus formed
by the end of the ligament, sub-quadrate; epidermis yellow
and purple brown, with green oblique rays, finely wrinkled,
smooth and shining; the wrinkles of the anterior wing, as they
ascend the wing, are curved anteriorly and continuous over
both wings; each valve furnished with a long, curved, lamel-
liform tooth, very small anteriorly to the beaks, larger and
longer posteriorly, pointed at both ends; anterior cicatrices
distinct ; posterior cicatrices confluent ; dorsal cicatrices situa-
ted in the cavity of the beaks, very perceptible; cavity of the
beaks wide and very shallow; nacre thin, pearly, and irides-
cent, with tints of salmon, white and purple; the undulations
very perceptible from the centre of the beaks along the base
of the tooth to the posterior dorsal margin.

Remarks.—All the specimens which I have seen of this
remarkable species were brought from Canton. The first
was received by Mr Hyde about two years since, and then
excited much interest with our conchologists. Several speci-
mens more perfect were brought last summer in the “Cale-
donia;” and from these specimens the description has been

OF THE FAMILY OF NAIADES, 447

made. That of Mr Hyde is a large, old, and valuable speci-
men, but has lost some of its important characters. Both
wings are destroyed, the beaks much eroded, and the epider-
mis black and much wrinkled, and the rays obsolete. The
remarkable waves at the base of the posterior wing are almost
obsolete, and the beauty of the nacre nearly destroyed by be-
ing thick and opake; cicatrices very perceptible. In this
specimen, and I believe it will occur in all adult individuals,
the only remains of the lamelliform tooth are in the termina-
tion of it under the ligament, about an inch long; the rest
of it is lost in the callus of the dorsal margin. Its dimen-
sions are

Diam. 2-1, Length 5:5, Breadth 7-1 inches.

In general form and character this species exteriorly resem-
bles most the Symphynota alata ; interiorly, except in colour,
the Symphynota levissima, herein described ; the shape of the
lamelliform tooth of which assimilates to it, with the excep-
tion of its being double. The teeth in both these species de-
scribe nearly the same are and take the same position. Both
species are alated anteriorly and posteriorly to the beaks.
The levissima differs in having no undulations, and possessing
obsolete rays, double teeth, and purple nacre.

The Dipsas plicatus of Leach bears a strong resemblance
to this shell. It differs, however, in the wings of the D. pli-
catus not being elevated, almost forming a line with the
beaks, in the latter not being connate, and in not being crown-
ed with undulations at the beaks. His description, however,
is so short and defective, and the drawing evidently so badly
executed, that I cannot determine in what other points it
may differ.

Schumacher’s Cristaria tuberculata bears a strong affinity
to this species also, as well in his description as his plate. He
describes and figures it, however, as being alated posteriorly,
and not anteriorly, and does not mention its being connate.
The fact of its possessing a divided lateral tooth, “callus pa-
rallelus bifidus,” proves that it is not our species.

YOL, 11..—5 X

448 NEW GENUS AND SOME NEW SPECIES

3. SympnynoTa ALATA.

Testa ovato-triangulari, transversim rugosa, sub-compressa ; valvulis
crassiusculis, earum marginibus dorsalibus alatis, et super ligamento
connatis ; dente cardinali in valvulis ambabus duplici, laterali in sinis-
tra tantum duplict, subcurvato; ligamento sub ala celato; natibus pro-
minulis ; margarita purpurea.

Shell triangular-ovate, transversely wrinkled, rather compressed ;
valves moderately thick, elevated into a high wing, and connate over the
ligament; beaks scarcely prominent; cardinal tooth double in both
valves; lateral tooth double in the left valve only, and slightly curved;
ligament concealed ; nacre purple.

Hab. our western waters.
Unio alatus. Say. Nicholson’s Encyclopedia (Am. Ed.)
Art. Am. Conch. pl. 4, fig. 2.*
Unio alata. Wamarck.
Unio alatus. Barnes. Silliman’s Am. Journ. Vol. VI.
Unio alata. Swainson.
Diam. 2, Length 4-7, Breadth, 6-9 inches.

Remarks.—In young specimens it appears disposed to be
connate anteriorly to the beaks also. The dorsal cicatrices
form quite a row across the cavity.

4, SYMPHYNOTA ComMPLANATA.

Testa ovato-triangulari, inequilaterali, transversim rugosa, compres-
sa; valvulis crassis; margine posteriori dorsali alata connataque ; dente
unico cardinalt in valvula utraque; plano irregulari calloso sub liga-
mento; natibus compressis, sub-prominulis ; ligamento celato ; marga-
rita alba, iridescentt.

Shell triangular-ovate,t inequilateral, transversely wrinkled, com-

* This figure was made from an imperfect specimen, the wing being mutilated.

} See Barnes’s description.

{ Mr Barnes says “ ovately quadrangular ;’’ but the shell is evidently more tri-
angular, as his figure displays it. See Silliman’s Am. Journ. Vol. VI. p. 278.

.

OF THE FAMILY OF NAIADES. ° 449

pressed; valves thick; posterior dorsal margin winged and connate; a
large cardinal tooth in each valve; an irregular callous plane under the
ligament ; beaks compressed and scarcely projecting ; ligament conceal-
ed; nacre white and iridescent.

Fox River. Mr Schoolcraft.
Hab. <~ Wisconsan. Captain Douglass.
Ohio. W. Cooper.
My Cabinet.
Cabinet of Mr Barnes.
Cabinet of Prof. Vanuxem.
Cabinet of the New York Lyceum.
Cabinet of Dr Mitchill.
Cabinet of the Academy of Natural Sciences.
Alasmodonta complanata. Barnes.
Diam. -9—1-4 inches. Length from beaks to base, 3 inches.
Breadth 5 inches.
Length from the top of the wing, 4-3—4-5 inches.*

Shell triangular-ovate, inequilateral, transversely wrinkled,
compressed, the largest diameter being nearly 2-3ds of the dis-
tance from the beaks to the base ; substance of the shell thick ;
valves elevated into a moderately sized wing over the ligament,
and connate; this wing is traversed at right angles to the
wrinkles, by obscure undulations reaching to the beaks; beaks
much compressed and scarcely projecting, crowned by seve-
ral double concentric undulations, which terminate in a point ;
ligament concealed in the wing; sinus subquadrate; epider-
mis dark brown and irregularly wrinkled; cardinal tooth
thick, elevated, sulcated, and diverging from the beaks ; a wide,
irregular callous plane extends under the ligament; cicatrices
in the anterior margin three, and irregular; in the posterior
margin two, confluent and scarcely perceptible; dorsal cica-
trices very perceptible; cavity of the beaks and disk small;
nacre white and iridescent.

Remarks.—This shell, first described by Barnes, is a rare

* See Barnes’s description; my specimen is rather more ventricose.

450 NEW GENUS AND SOME NEW SPECIES

and beautiful species. It is peculiar in its very much com-
pressed beaks, and in its greatest diameter being but a short
distance above the basal margin.

5. Symenynora Compress. Plate XII. fig. 22.

Testa transversim elongatd, inequilaterali, valde compressa, elliptica ;
valvulis tenuibus ; natibus sub-prominulis, undulatis ; dente cardinali
prominente ; laterali parvo.

Shell transversely elongated, inequilateral, compressed, elliptical ;
valves thin; beaks scarcely prominent, undulated ; cardinal tooth promi-
nent; lateral tooth small.

Ohio. 'T. G. Lea.
Norman’s Kill, near Albany. Dr Eights.
My Cabinet.
Cabinet of Prof. Vanuxem.
Cabinet of Dr Eights.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.
Cabinet of the New York Lyceum.
Diam. °S, Length 1-7, Breadth 2-8 inches.
Shell transverse, much compressed, elliptical; substance of

the shell rather thin; beaks slightly elevated, not decortica-
ted, beautifully crowned with small double concentric undu-
lations, points of the beaks almost white; ligament concealed
within the valves; dorsal margin rather elevated posteriorly
to the beaks; posterior margin sub-angular; posterior basal
and basal margins curved; anterior and anterior dorsal and
basal margins rounded; epidermis olive-green, slightly wrin-
kled and glabrous; radiations over the whole disk; cardinal
tooth prominent and curved, in the left valve with three pro-
tuberances, the posterior the highest, sloping to the end of the
lateral tooth, the anterior the lowest; in the right valve one
rather large, which closes between the first and second of the
left; lateral tooth short and nearly straight, passing from

Hab. 3

OF THE FAMILY OF NAIADES. 451

the very point of the beaks, in the right valve lamellar near
the termination, and abrupt; in the left acicular, the channel
being only large enough to admit of the edge of a penknife;
in the right valve the cardinal and lateral teeth are entirely
separated by a cavity formed by the tooth of the other valve,
this cavity is at the very point of the beak, and therefore the
valve has little or no cavity ; in the left valve the large recurv-
ed tooth forms a beautiful angular cavity; anterior cicatrices
distinct; posterior cicatrices confluent; dorsal cicatrices situ-
ated at the point of the cavity of the beaks; cavity of the shell
very shallow; nacre delicate salmon colour towards the beaks,
bluish towards the margin.

Remarks.—This is a singular and beautiful shell. — Its

cardinal and lateral teeth are very remarkable. The first
being high in the left valve over the cavity of the beak, while
in the right it is there depressed ; the latter is short and lam-
elliform at termination. ‘The beaks are equally remarkable,
being finely undulated; the epidermis is so thin and delicate
as to give them almost a white appearance. The rays are
broader and more full than in any shell I have seen; they
diverge in all directions from the point of the beaks to the
margin.
The specimen belonging to the cabinet of the New York
Lyceum, was kindly sent for my inspection by W. Cooper,
a member of that valuable institution. It was given by Dr
Eights to Mr Barnes, and by the latter labelled “U. alasmo-
dontina.” My description was written some years since, but
remained unpublished until I should have an opportunity of
examining other specimens.

VOL. IlI.—5 ¥

452 NEW GENUS AND SOME NEW SPECIES

6. SympuynoTa GRACILIS.

Testa sub-triangulari-ovatd, inequilaterali, transversim rugosa, sub-
compressa ; valvulis tenuibus fragilibusque ; margine posteriori dorsalt
sub-alatd, connataque; dente cardinali in valvula dextra elevato, recurvo ;
natibus sub-prominulis ; ligamento celato; margarita violaceo-purpurea
et iridescente.

Shell sub-triangular-ovate, inequilateral, transversely wrinkled, rather
compressed ; valves thin and fragile; posterior dorsal margin connate,
wing but little elevated ; cardinal tooth of right valve elevated, recurved ;
beaks scarcely prominent; ligament concealed; nacre pearly, violet-
purple, and iridescent.

Ohio. T. G. Lea.
Wisconsan. Mr Schoolcraft.
My Cabinet.
Cabinet of Mr Barnes.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of Mr Swainson.
Cabinet of the New York Lyceum.
Cabinet of the Academy of Natural Sciences.
Unio gracilis. Barnes. Silliman’s Amer. Journ. Vol. VI.
174.
: Unio fragilis. Swainson*.
_ Unio planus. Barnes.
Diam. 1—1-2, Length 2-2—2:-5 inches.
Breadth 3-1—4:1 inchest.

Shell sub-triangular-ovate, inequilateral, transversely wrink-
led, rather compressed; substance of the shell thin ; valves ele-
vated into a small wing over the ligament and connate ; beaks
slightly prominent, pointed, having two or three minute ele-
vations; ligament concealed in the wing; epidermis yellow-

Hab. ;

* JT have retained the specific name of Mr Barnes in preference to that of Mr
Swainson in the right of priority. Mr B. published in January 1823. Mr S.’s
dedication of 3d vol. of his Zool. [lus., in which the fragilis is described, is dated
Oct. 1823.

+ See Barnes’s description.

OF THE FAMILY OF NAIADES. 453

green, finely wrinkled, obscurely radiated and glabrous; marks
of growth very perceptible; cardinal tooth of right valve
crest-like, recurved, and clasping the side of the opposite one ;
lateral teeth lamelliform and curved; anterior cicatrices dis-
tinct ; posterior cicatrices confluent; dorsal cicatrices form a
line across the cavity of the beaks, and are very perceptible ;
cavity of the beaks very wide and shallow; nacre pearly,
bluish-white, violet-purple and iridescent.

Remarks.—Mr Barnes noticed this as a connate shell. His
description of the cardinal tooth does not agree with my spe-
cimens, except in the younger ones, in which this tooth is
more lamellar. The recurved tooth hooking or clasping the
other, when the valves are closed, is very remarkable.

In some specimens the lateral and cardinal teeth form an
uninterrupted curve line, when the cardinal tooth is quite
lamelliform ; in others the latter is small and lobed, age pro-
ducing much effect on it in this respect.

7. SympnynoTa Tenvurissmma. Plate XI. fig. 21.

Testa angusto-elliptica, inequilaterali, transversim rugosd, compressa ;
valvulis tenuissimis fragillimisque; margine dorsali connaté; dente
cardinali prominentia exigud, laterali unico et aciculari in valvuld utri-
que; natibus depressis; ligamento celato; margarita ceruleo-albé et
purpurea, tridescente.

Shell narrow-elliptical, inequilateral, transversely wrinkled, com-
pressed ; valves very thin and very fragile ; dorsal margin connate ; car-
dinal tooth a small lobe ; lateral tooth acicular and single in both valves;
beaks depressed ; ligament concealed; nacre bluish-white and purple,
iridescent.

Hab. Ohio. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.

454 NEW GENUS AND SOME NEW SPECIES

Diam. °6, Length 2-2, Breadth 2°5 inches.

Shell narrow-elliptical, inequilateral, transversely wrinkled,
much compressed ; substance of the shell very thin ; valves con-
nate over the ligament, and not elevated into a wing; beaks
scarcely prominent, pointed, nearly terminal; epidermis wrin-
kled, yellow, with very oblique green rays, which, when ap-
parent, give a greenish hue to the shell; rays more numerous
and perceptible along the umbonial slope; marks of growth
very perceptible; greatest diameter along the umbonial slope ;
cardinal tooth of right valve a small lobe closing into a de-
pression of the margin of the left valve; lateral teeth acicu-
lar, single in both valves, and nearly or quite direct; anterior
cicatrices distinct; posterior cicatrices copfluent; dorsal cica-
trices form a line across the cavity of the beaks, and are very
perceptible; cavity of the beaks scarcely apparent; nacre
bluish-white, purple about the region of the teeth and the
cavity of the beaks.

Remarks.—This interesting species is the most fragile and
thin of all the family of the Naiades which I have seen. 'The
epidermis seems in some specimens to prevail over the sub-
stance of the shell, which is so extremely brittle as almost to
be destroyed in our cabinets by its contraction from the effect
of the atmosphere. The beaks are so nearly terminal that it
somewhat resembles the modiolain thisrespect. Itis the near-
est approach to the nodonta, having but the rudiments of
teeth; and I am much disposed to believe that the “ 4nodon
purpurascens” of Swainson is analogous to this shell. He had
seen but one perfect specimen sent him by Mr Rafinesque from
the “back settlements.” I have seen many specimens of the
tenuissima, all of which have the rudiments of the cardinal and
lateral teeth. This shell exhibits to us the necessity of resort-
ing toamore natural definite division of Naiades than that of
the teeth. The ¢enuissima resembles most the gracilis. ‘They
differ, however, in the latter being much larger, more ovate,
heavier, more ventricose, and not radiate. The teeth of the
gracilis are well defined, which is not the case with this.

OF THE FAMILY OF NAIADES. 455

8. SympHynoTa OcHRACEA.

Testa sub-ovatd, inequilaterali, transversim rugosa, inflata ; valvulis
post ligamentum connatis, tenuibus, fragilibus, et sine ala; dentibus
cardinalibus et lateralibus curvam lineam facientibus ; natibus promi-
nentibus ; ligamento conspicuo ; margarita ceruleo-alba et ochracea.

Shell sub-ovate, inequilateral, transversely wrinkled, inflated ; valves
thin and fragile, connate behind the ligament, not winged ; cardinal and
lateral teeth forming a curve line; beaks prominent; ligament visible;
nacre bluish-white and ochraceous.

Hab. Schuylkill and Delaware.
My Cabinet.
Cabinet of Mr Say.
Cabinet of Prof. Vanuxem.
Cabinet of Mr Hyde.
Cabinet of the Academy of Natural Sciences.
Cabinet of Dr Griffith.
Cabinet of P. H. Nicklin.
Peale’s Museum.

Unio oehraceus. Say. Nicholson’s Encyclopedia, Art.
Am. Conchol. pl. 2, fig. 8.
Diam. 1:3, Length 1-9, Breadth 2-9 inches.

Shell sub-ovate, inequilateral, transversely wrinkled, infla-
ted ; dorsal margin rectilinear; valves thin and fragile, con-
nate behind the ligament, not winged; beaks full and pro-
minent, with several concentric undulations; ligament not
concealed; epidermis glossy, varying from yellow ochre to
brown ochre, marked with oblique rays, most abundant
behind; cardinal and lateral teeth lamelliform, forming a
curve line, in the right valve the cardinal tooth is double,
in the /eft single; anterior cicatrices distinct; posterior cica-
trices confluent ; dorsal cicatrices form a row across the ca-
vity of the beaks, very perceptible; cavity of the beaks large ;
nacre bluish-white and ochraceous; along the anterior basal
margin thicker and tinged with red; posterior margin iri-
descent.

VOL. III.—5 Z

456 NEW GENUS AND SOME NEW SPECIES

Remarks.—This is a beautiful shell. It is remarkable in
being connate behind the ligament; this connection, how-
ever, is very small, and only perceptible in perfect specimens ;
in the old ones it is separated. Fine specimens have been in
our cabinets for years without our observing they were con-
nate. The cardinal tooth being double in the right valve
seems to have escaped the attention of the observant Mr Say.

9. SympuynoTa CyGnea.

Testa ovatd, antice lata et rotundata, irregulariter transversim ru-
.gosa ; natibus retusis ; valvulis tenuibus et post ligamentum connatis.

Shell ovate, wide before and round, with irregular transverse wrin-
kles ; beaks not prominent; valves thin and connate behind the liga-
ment.

Hab. rivers and lakes of Europe.
My Cabinet.
Mytilus cygneus. Lin. Gmel. p. 3555.
Anodonta cygnea. Lam.

Remarks.—It is a matter of surprize to me that this shell,
so long known and so often described by European concho-
logists, should not have been before observed to be connate. It
has not to my knowledge been thus described. Among about
a dozen specimens received from various parts of Europe, I
have two which are decidedly and undoubtedly connate. One
was sent to me by Count de Yoldi of Copenhagen, the other
by W. Swainson, Esq. of London. These are the only spe-
cimens I have seen with the dorsal margin unfractured, and
it may be that even in their native beds they rarely exist in
a perfect state with regard to this part. Young specimens
would be more likely to be found perfect, if taken from pools
or lakes where they remain undisturbed by the attrition of
sand, &c. carried over them by the action of the water.

ARTICLE V.

Observations on the Naiades, and Descriptions of New Species of that and
other Families. By Isaac Lea. Read before the American Philo-
sophical Society, May 7, 1830.

SINCE I presented my last paper on the Naiades, which was publish-
ed in the third volume of the Society’s Transactions, I have been fortu-
nate in obtaining many species hitherto undescribed.

I have possessed for several years many individual specimens which
I supposed to be new, but which I deferred describing until I should
possess of each kind individuals of different ages. My late acquisitions
have converted my suppositions into certainty; and I now offer the
following descriptions with a view to their publication in the fourth
volume of the Society’s Transactions, to be accompanied by figures
executed like those attached to my last memoir.

In that memoir I took occasion to make some remarks on the “ele-
vations on the surface of the disks.” I had not at that time satisfied
myself entirely in regard to the manner in which these were accom-
plished by the animal. Some fine specimens of the Unio cornutus,
in all the stages of growth, having since been procured, I have been
able to trace these formations through every degree.

It will be observed on examination, that the horns alternate ; that is,
those on one valve are not placed opposite to those on the other;
consequently one is made at a time. The animal deposits the secreted
carbonate of lime on the outside of the edge of one valve, where the
horn is to be formed, and on the inside of the edge of the other; the

64 OBSERVATIONS ON NAIADES,

consequence of which is, that when the horn is sufficiently elevated,
the line of the opening at the base of the shell has diverged from the
plane of the valves into an obtuse angle at this point. The deposit
of the secretion is then reversed, al the line of the opening at
the base is soon restored to the plane of the valves. If another
horn is to be formed, this lateral increase of the edges is carried on
until the same effect is produced on the other side of the shell. The
natural consequence of this alternation is a depression on the outer
side of one valve corresponding to the horn on the other, and thus we
ever find it. In one of my specimens the turn is so short, after the
formation of the last horn, that this side passes over the other and forms
a plane one third of an inch, so that the specimen presents the curious
phenomenon of a shell standing erect on its base, when placed on a
smooth surface.

The plice or folds are formed on the same principle. In the basal
and posterior margins of the plicated species we may see the line of
opening undulated by every fold, and when the deviation from the
plane takes place in one valve it is followed up always by the other.
In the Unio tuberculatus, when tuberculated to the edge, these tuber-
cles cause it to be crenate. .

Inthe Unio metanever we are presented with different elevations on
the disks. This beautiful and interesting species is furnished with
elevations, small at the beaks, and enlarging towards the base along
the umbonial slope. These elevations are antagonist, and being
formed at the same time, we consequently see, in a certain stage of
growth, quite a knob at the angle of the basal margin. In the Unio
lacrymosus, which is furnished with smaller elevations on the umbonial
slope, we find them to alternate.

When making some observations on “ colour” in my last memoir, I
mentioned that “the green irregular spots and marks” on the interior
of the valves were “ eorentale perhaps the effect of disease.” Subse-
quent observation led me into an examination of these marks, and the
result is a perfect conviction of their being epidermal matter, evidently
placed occasionally between successive layers of nacre, as it were in
anticipation of a future erosion of the beaks. In a specimen of Unio
pustulosus (herein described) in my cabinet, erosion has taken place

AND DESCRIPTIONS OF NEW SPECIES. 65

into the mass of its thick beaks to the distance of one third of an inch,
where a false beak is exhibited covered with a thin layer of epidermal
matter, and a fracture of this false beak displays another within,
entirely covered with the same matter. In the same specimen, which
is more eroded than any I have seen, a considerable portion of the
cardinal tooth is visible from the exterior, and this portion is also
covered with epidermal matter.

I willtake the opportunity here to remark on the absolute necessity
of studying the different ages of the species of this family, to enable us
to decide upon new species. I have never been more thoroughly
convinced of any thing than this. When I have been able to do so, I
have always placed in my cabinet at least three or four specimens of
different ages. Four years since, I obtained a large old specimen of
the Unio multiplicatus (herein described), which I placed with my
specimens of Unio plicatus. 'Two young specimens were received at
the same time, and so totally different were they in appearance, that
it did not occur to me there was any similarity between them and the
old one. These were placed with the Unio tuberculatus, in the belief
of their being a compressed variety of that species. A specimen
subsequently received, which furnishes the engraving, proved at once
their identity by displaying the numerous undulations in the region of
the beaks.

I have continued to give my attention to the habits of the animals
of this family, but I have in vain attempted to satisfy myself as to the
nature of their food. Dissatisfied with the results of the observations
mentioned in volume third, I procured, among other species, a fine
Unio cariosus, the valves of which were much more gaping than usual.
Selected specimens of various species were placed in a glass vase, in
the bottom of which was placed clean white sand, so that their natural
beds might be somewhat imitated. In this vessel they assumed their
natural position by pushing the sand behind them with the protruded
foot, thus forming a pit into which the base of the shell gradually fell,
the ligament taking the most elevated situation. In this position they
soon began to travel round the vessel, and this locomotion continued
for some days, when it ceased entirely.

Their extreme timidity or apprehension on the approach of danger

Vou. IV.—R

66 OBSERVATIONS ON NAIADES,

was very evident. At first the slightest agitation or movement of the
vessel caused them to close their valves instantly. Being almost daily
disturbed, this alarm after a time ceased, particularly with my fine
cariosus, which now suffered even the agitation of the water without
closing the valves, stretching out its fine dark and beautiful tentacula
from the borders of its mantle, and forming by the contact of its edges
two openings one below the other.

From the superior of these openings the constant stream ejected could
be plainly perceived for two inches elevating the water at its surface.
Being very anxious to ascertain through what part the water necessary
to supply this stream was carried into the shell, I discovered it, after
many experiments, to pass in by the inferior opening ; that it passed
out by the superior one had always been evident. This operation
was unremitted while the water was fresh; when left unchanged for
some days this current invariably ceased. Doubting the correctness of
my former idea, as to the probability of* their feeding on animalcula,
from the circumstance of finding the passage of the water to exist only
while fresh, and never when animalcula were visible even with a
microscope of great power, I instituted some experiments by passing
pieces of bread, very small pieces of worms, &c. between the tentacula.
Several of them would sometimes remain for some minutes within
the mantle and so far within as to be invisible, but they were in every
case in a very short time thrown out with a rapid and sudden jet of
water tothe opposite side of the vessel.

These experiments were frequently repeated during the course of a
year upon the same specimen, and the result was uniformly the same.
No food introduced into the shell could be ascertained to have remained ;
it may therefore be pretty safely concluded, that neither animalcula
nor food in a more solid state are necessary to the nourishment of the
Naiades. What thenare we to conclude itto be? Would the decom-
position of water serve the purpose of nourishment as well as breath-
ing? Certain it is, that during the many years I have been in the habit
of almost constantly having them alive for examination, dissection, &c.
I have never in any instance given them food, unless it was conveyed
invisibly to them in the pure water with which our city is supplied
through our works from the river, and which was given them every
few days.

AND DESCRIPTIONS OF NEW SPECIES. 67

When I established the genus Symphynota*, I remarked on the
difficulties attending the present generic divisions of the family Naiades.
Since that period a closer attention to these divisions has convinced
me of the entire impossibility of defining limits to them. The
hinges in the species of the different genera glide or shade away so
completely into each other, that I have no hesitation in saying it is
entirely impossible for any naturalist to mark out a line of unvarying
character to most of them. It must therefore be conceded that other
characters are required for generic divisions.

If we examine the

Anodonta cygnea (Lam.), we find the margin under the beak and
ligament to be an uninterrupted line. In the

fridina nilotica (Sowerby) this line is slightly interrupted under the
point of the beak. In the

‘Anodon areolatus (Swainson) we have this interruption more
distinctly marked, the elevations being larger and more curved, evi-
dently forming an incipient tooth which approaches very closely to the

Alasmodonta marginata (Say), and forms with it a natural link.
The next in the chain appears to be the

Alasmodonta rugosa (Barnes), which has an incipient lateral tooth ;
and that which follows very closely is the

_ Unio calceolus (Nob.), which has the lateral tooth very slightly more
defined than the preceding. In the

Symphynota compressa (Nob.), we have the tooth more perfect and
extended, forming a moderately well characterised lateral tooth of the
genus Unio. The well known

Unio pictorum (Mya pictorum, Lin.) presents us with cardinal and
lateral teeth completely formed. In this genus, the Unio, we have
an infinite variety in the forms of teeth. In the

Symphynota alata (Nob.), the cardinal and lateral teeth are com-
pressed in most specimens; and the next change we find, is in the

Hyria avicularist (Lam.), in which the cardinal tooth is somewhat

* See Vol. III. p. 442.

} When the animal of this genus shall be examined, it will be found, I have no doubt, to
differ from the Unio, Anodonta, &c. For notwithstanding Lamarck’s description, “ elles ont
intérieurement les impressions musculaires latérales des Nayades,” T have discovered that the

68 OBSERVATIONS ON NAIADES,

lamellar and forms nearly a line with the lateral tooth. The next
“nuance” is in the

Symphynota levissima (Nob.), which possesses lamelliform cardinal
and lateral teeth forming nearly a complete arc. ‘Then follows the

Symphynota bialata (Nob.), the uninterrupted curved tooth of which
is little more than an elevated line under the ligament and beaks. As
far as one may be able to judge from a bad description and very bad
drawing, the

Dipsas plicatus (Leach) may be with propriety placed at the end of
this suite.

In the U. oriens described in this paper, we have a peculiarity in
the formation of the termination of the lateral tooth, which is en-
larged.

Under the impression, therefore, that the teeth in the Family Maiades
do not form a sufficient distinctive character to compose genera, I
propose to make a “division” of the family, the distinctive character
of which will be valves free and valves connate ; the genus Unio to
include the first, the genus Symphynota to include the last. If subse-
quent groups be necessary, these may be composed of subgenera.

In my catalogue* of species, which I presumed should be considered
as established, I gave the undulatus of Barnes as a synonym, consider-
ing it as a variety of the plicafus. Conversing with that naturalist
over his cabinet some time before his death, he expressed himself as
being very much ofthat opinion. At that period neither of us had
seen a young specimen of this species; very recently I have been for-
tunate enough to obtain several, and the examination of the beaks of
these, which are nearly perfect, convinces me, that although the wadu-
latus resembles the plicatus in its general characters, yet, that the
beaks are sufficiently dissimilar to make them specifically different.

extensor muscle of the foot is attached to the internal base of the cardinal tooth and there
forms a remarkable cicatrix, which of course is over the large anterior (posterior of Lam.)
cicatrix, while in all the numerous species of Naiades which I have examined, the cicatrix of
the extensor muscle has been situated below the large anterior cicatrix. In anatomical struc-
ture they must therefore differ.

* Transactions, Vol. III.

PL... Vol .4,

Mh mT

SNC PU ss

RUT Ctr i

JN cence pr tanec ZARA IS ROMS

Cnio trapezordes

AND DESCRIPTIONS OF NEW SPECIES. 69

Unio Trarezores. Plate III. fig. 1.

Testa trapezio simili, inequilaterali, transversd, postice undulata; valvulis
crassis ; dentibus cardinalibus utriusque valvule duplicibus ; lateralibus laminatis
curvisque; margarita purpurea et iridescente.

Shell trapezoidal, inequilateral, transverse, undulated behind; valves thick ;
cardinal teeth double in both valves; lateral teeth curved and lamelliform ; nacre
purple and iridescent.

Hab. Lake St Joseph, Louisiana. J.T. Griffith, Esq.
My Cabinet.
Cabinet of Prof. Vanuxem.

Diam. 1:9, Length 2-6, Breadth 4-3 inches.

Shell trapezoidal, more angular behind, transverse, undulated on
posterior half ; umbonial slope elevated almost into a carina, anterior
to which the undulations are oblique and disposed to lie parallel to
each other; posterior slope large and elevated into a carina; sides
flattened ; substance of the shell thick ; beaks slightly prominent and
incurved; ligament large, long and slightly curved ; epidermis black
and wrinkled; cardinal teeth double in both valves, crenate and
deeply cleft in the left valve ; lateral teeth, long, curved and lamelli-
form; anterior cicatrices distinct and rough; posterior cicatrices con-
fluent ; dorsal cicatrices situated under the posterior part of the cardinal
tooth; ventral cicatrix very perceptible; cavity of the beaks wide and
deep; nacre dark purple and iridescent.

Remarks.—This highly interesting species came into my possession
through the kindness of J. 'T’. Griffith, Esq. of Natchez. It approaches
the U. plicatus* of Lesueur, more nearly than any other species with
which I am acquainted ; it differs, however, from that species, strik-
ingly, in the colour of the nacre, in the general outline of the shell

* For the authority of this name and author, see Am. Conch. article Unio crassus ; also
Barnes’s article in Silliman’s Journal, Vol. VI. p. 120,

Vou. [V.—S

70 OBSERVATIONS ON NAIADES,

and in its remarkable square sides. The great peculiarity of this
species is in its possession of a small cicatrix (which I propose to call
the ventral cicatriz) anterior to the central part of the cavity of the
shell. In no other species have I ever met with the slightest indi-
cation of this cicatrix, although I have examined numerous larger and
more globose specimens of various species with this view.

Unto Mvtrirricatus. Plate IV. fig. 2.

Testa trapeziali, inequivalvi, oblique transversa, maxime undulaté ; valvulis
crassissimis ; dentibus cardinalibus crassts, lateralibus longis curvisque; margarita
alba et iridescente.

Shell trapezoidal, inequivalve, obliquely transverse, much undulated ; valves very
thick ; cardinal teeth thick; lateral teeth long and curved ; nacre pearly white and
iridescent.

Hab. Siaee 6 River. Prof. Vanuxem.
Ohio River. T. G. Lea.
My Cabinet.
Cabinet of Prof. Vanuxem.

Diam. 2:2, Length 3:8, Breadth 5-6 inches.

Shell trapezoidal, obliquely transverse, undulated except near the
anterior margin, compressed towards basal and posterior margins ;
undulations diverge from the umbonial slope and in the superior part
curve towards the dorsal margin which is carinate ; substance of the
shell very thick ; beaks slightly prominent and rugose with undulations
extending over the umbones which are flattened ; ligament large, long
and curved; epidermis black and much wrinkled ; cardinal teeth thick
and suleate; lateral teeth large, long and slightly curved ; anterior
cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices
situated on the under side of the plate between the cardinal and lateral
teeth; cavity of the beaks rather large and rounded; nacre pearly
white, iridescent and surrounded by a distinct dark margin.

Remarks.—This fine large species was one of many fine shells

PL.1V.Vol 4

Tnio multiplicates

qs
=a0tl
F

Blin; Woe

ut

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es
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Ar LOE
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ee
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AND DESCRIPTIONS OF NEW SPECIES. 71

brought by Prof. Vanuxem from the western states. It is very nearly
allied to the plicatus (Lesueur) in its general characteristics, but when
the beaks are not much eroded, it may be at once distinguished from
that species by the numerous small irregular undulations which sur-
round and cover the beaks, and of which the plicatus is entirely destitute
except at the very tip of the beaks ; where the small folds are entirely
unconnected with the large ones. In a very young state no two
species, scarcely, can be more different, the multiplicatus being entirely
covered with undulations, while the plicafus possesses none, except
the small ones at the tip. In this state it resembles exceedingly the
tuberculatus of Barnes, and when I received my first specimen, I
referred it to that species, considering it a variety, and should most
probably have continued to be of that opinion, had I not obtained a
large specimen. sufficiently perfect to display the irregular undulations
in the region of the beaks. The facts mentioned above, show the
absolute necessity of studying the young in making ourselves acquainted
with the species.

Unto Asrperrimus. Plate V. fig. 3.

Testa sebquadrangulari, inequilaterali, postice biangulari, natibus ad baseos
marginem sulcata et nodulis instructa; valvulis percrassis ; natibus elevatis; dentibus
cardinalibus pregrandibus, lateralibus magnis subrectisque ; margarita pulchra et
iridescente.

Shell sub-quadrangular, inequilateral, biangular behind; sulcated from beaks
to basal margin, thick and noduled; valves very thick; beaks elevated ; cardinal
teeth very large ; lateral teeth large and nearly straight ; nacre beautifully pearly
and iridescent.

Hab. Ohio River. T. G. Lea.
My Cabinet.
Cabinet of T. G. Lea.
Cabinet of Lyceum of Natural History of New York.
Diam. 2-3, Length 3-6, Breadth 4-8 inches.
Shell sub-quadrangular, biangular behind, sulcated from beak to

72 OBSERVATIONS ON NAIADES,

basal margin, roughly noduled and thick; basal margin emarginate ;
substance of the shell thick ; beaks prominent, retuse ; noduled along
the umbonial slope and before the furrow, which is smooth; posterior
slope covered with nodules; nodules posterior to the furrow are dis-
posed to be transverse and on the umbones erect or recurved ; ligament
large; epidermis wrinkled and fuscous in adult specimens,—in younger
specimens it is yellowish brown with obsoiete rays; cardinal tooth
very large, widely cleft, suleated and crested in the left valve, in the
right valve emerging from a pit; posterior cicatrices confluent; ante-
rior cicatrices distinct, the great one deep ; dorsal cicatrices situated on
the under part of the cardinal tooth; cavity of the beaks angulated,
large and deep ; nacre beautifully pearly white and iridescent.

Remarks.—This fine and interesting species is nearly allied to the
U. laerymosus (Nob.). It differs from it distinctly in the possession
of nodules which are rough and disposed to be erect and transverse.
The tubercles of the /acrymosus take a direction towards the basal
margin, and are similar to tears flowing down the cheek. The pos-
terior margin in the present species is more protruded, while the area
of the anterior portion is smaller than that of the lacrymosus. It
cannot be mistaken for the U. metanever (Rafinesque), which possesses
large elevations along the umbonialslope. In younger specimens than
the one represented here the basal and posterior margins are more
rounded. :

Unto Coneareus. Plate VI. fig. 4.

Testa rhomboideo-elliptica, transversa, inequilaterali; valvulis tenuibus; natibus
subundulatis; dente cardinali obliquo compressoque ; dentibus lateralibus longis, et
prope terminos posteriores auctis ; margarita sericea et iridescente.

Shell elliptico-rhomboidal, transverse, inequilateral ; valves thin ; beaks slightly

undulated ; cardinal tooth oblique, compressed; lateral teeth long and enlarged
towards the posterior end ; nacre satinlike and iridescent.

Hab. Congaree River, South Carolina.

Bie Vale aviole 4:

S— — — Af
ee

in
eee

Rh ace seA

Cnio ortns .

Unto congreus Unio brevidens

Drawn & Eng’d by J Drayton

AND DESCRIPTIONS OF NEW SPECIES. 73

My Cabinet.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of H. C. Carey.
Cabinet of the Academy of Natural Sciences, Philadelphia.
Diam. -7, Length -1, Breadth 1-6 inches.
Shell elliptico-rhomboidal, transverse, somewhat flattened at the
sides; posterior slope furnished with slight undulations; substance
of the shell thin; beaks slightly prominent, and furnished with par-
allel concentric undulations near the tips; ligament short; epidermis
yellow, and yellowish brown; rays green and numerous; cardinal
tooth oblique, compressed, and slightly cleft in the left valve—in the
right single; lateral teeth long, slightly curved and enlarged towards
the posterior end ; anterior cicatrices distinct ; posterior cicatrices con-
fluent; dorsal cicatrices situated under the plate, between the cardi-
nal and lateral teeth; nacre satin like, and beautifully iridescent.

Remarks.—I obtained several specimens of this shell, on the shores
of the Congaree, at Columbia, 8. C. It resembles the radiatus (Gme-
lin) and complanatus* (Solan.), which species are frequently mistaken
for each other, and this may readily be confounded with either of
them. It has, like the radiatus, many rays, but differs in being more
angulated on the umbonial slope, and in measuring less from the pos-
terior dorsal margin to the basal margin. It differs from the com-.
planatus in its rays, and in having slight undulations on the posterior
slope. It is more diminutive in size than either, not being more in
volume than one-fifth of the complanatus from the same locality.

—_—_—_

Unio Ortens. Plate VI. fig. 5.

Testa longo-ovata, transversd, inequilaterali, compressa et radiis pulcherrimis
picta, valvulis tenuibus; natibus subprominulis et retusis ; dentibus cardinalibus

* For reclamation of this species, see Vol. III. p. 416.

Vou. IV.—T

74 OBSERVATIONS ON NAIADES,

parvis et imperfectis, lateralibus imperfectis et indivisis ; margarita ca@ruleo-alba,
iridescente, et in natium cavo purpured.

Shell long-ovate, transverse, inequilateral, compressed and beautifully rayed ;
valves thin; beaks scarcely prominent and retuse; cardinal teeth small and imper-
fect ; lateral teeth imperfect and divided ; nacre bluish white, iridescent and purple
in the cavity of the beaks.

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of R. Peter, Pittsburgh.
Cabinet of Dr Hildreth, Marietta, Ohio.

Diam. °5, Length 1:1, ‘Breadth 2:8 inches.

Shell long-ovate, transverse, compressed; substance of the shell very
thin; beaks scarcely prominent, and situated towards the anterior mar-
gin; ligament linear; epidermis slightly wrinkled, yellowish, with ob-
lique interrupted green rays, which enlarge posteriorly ; cardinal teeth
very imperfect; lateral teeth straight, very imperfect, (having little or
no longitudinal division, even in the left valve) enlarged at posterior
termination ; anterior cicatrices distinct ; posterior cicatrices confluent ;
dorsal cicatrices situated in the centre of the cavity of the beaks; cavity
of the beaks wide and very shallow; nacre bluish white, iridescent,
purple in the cavity of the beaks.

Remarks.—The specimen which is here described and figured, was
sent to me three or four years since, and has never ceased to excite in
me great interest and attention. The very imperfect state of the
teeth compelled me to doubt of the propriety of erecting it into a
new species, although the specimen bore no appearance of a malforma-
tion in any other part, however different it was from other species of
the family I had seen. Two other specimens, one of which is young,
having recently come into my possession, prove to possess precisely the
same characters in every respect, and the only difficulty which now
stood in the way of giving it a place in our systems was to determine
its genus! It appears to me, for the present, most proper to place it
with the Uniones. It cannot be placed with the Anodonta of Lam. for
he describes that genus as having “cardo linearis edentulus.” It
would be equally difficult to class it with the Mlasmodonta of Say, for

AND DESCRIPTIONS OF NEW SPECIES. 75

that conchologist says, “hinge with a primary tooth in each valve.” In
the oriens the cardinal and lateral teeth are equally imperfect, and in
this respect it resembles the U. soleniformis (Nob.), though much less
defined. Under these circumstances, it appeared necessary to give ita
place with the Uniones.

Unto Breyipens. Plate VI. fig. 6.

Testa subtriangulari, inequilaterali, transversé ; valvulis crassis ; dentibus car-
dinalibus modicis, lateralibus curvis, brevibus, crassisque ; margarita alba.

Shell subtriangular, inequilateral, transverse ; valves thick; cardinal teeth rather
small; lateral teeth curved, short, and thick; nacre pearly white.

Hab. Ohio, William Cooper.

My Cabinet.
Cabinet of Lyceum of Natural History of New York.
Diam. ‘8, Length 1:2, Breadth 1-7 inches.

Shell sub-triangular, angular behind, transverse; umbonial slope
curved ; sides flattened ; substance of the shell thick; beaks slightly
prominent ; ligament short; epidermis yellow, wrinkled; rays small,
slightly curved and interrupted; cardinal tooth rather small, slightly
elevated and widely cleft in the left valve, single and emerging from
a pit in the right valve ; lateral teeth curved, short and thick, posterior
and anterior cicatrices both distinct ; the smaller posterior one be-
ing placed directly over the larger and beneath the point of the lateral
tooth ; dorsal cicatrices situated on the under part of the cardinal tooth ;
cavity of the beaks arched, shallow ; nacre pearly white.

Remarks.—For this interesting and fine species we are indebted to
the liberality of the members of the Lyceum of Natural History of
New York, who, in accordance with their known zeal in the promotion
of natural science, promptly passed a vote to permit their new fluvia-
tile shells (herein described) to be described for, and inserted in our
Transactions, under the impression that science would be benefited by

76 OBSERVATIONS ON NAIADES,

their being embodied in one paper with those which I was about to
publish. This species somewhat resembles U, triangularis of Barnes.
It differs from it in being less ventricose, more ponderous, possessing
thicker teeth and in the rays which are interrupted indistinct lines.

Unto Pustunosus. Plate VII. fig. 7.

Testa modice producta, equilaterali, inflata, dimidio postico tuberculata; valvu-
lis crassis; natibus prominentibus et ad apices granulatis; dentibus cardinalibus
subgrandibus ; lateralibus brevibus, crassis, rectisque; margarita alba et irides-
cente.

Shell rather elongated, equilateral, inflated, tuberculated on posterior half; valves
thick ; beaks elevated and granulated at tip; cardinal teeth rather large; lateral
teeth short, thick and straight ; nacre pearly white and iridescent.

Hah wae 1. G. Lea.
* 2 Alabama river, Judge Tait.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of H. C. Carey.
Cabinet of the Academy of Natural Sciences of mie tae
Cabinet of Peale’s Museum.
Unio verrucosus. Var. b? Barnes.
Diam. 1-4, Length 2-2, Breadth 2-1 inches.
Shell rather elongated, equilateral, inflated, irregularly tuberculated
on posterior half, but not on the first and second growths; tubercles
generally large; substance of the shell thick; beaks elevated and
granulated at tip ; ligament short and thick; epidermis bright brown ;
a single broad interrupted ray passes from the beak nearly to the cen-
tre of the disk ; cardinal tooth rather large and widely cleft in the
left valve—single and emerging from a pit in the right valve; lateral
teeth short, thick and straight; anterior and posterior cicatrices both
distinct; dorsal cicatrices situated on the under part of the cardinal

PL.VIL Vol.4.

tig
mL ey,

Unio stapes.

Unio pustulosus. Cnio pustulatus,

Drawn. by IDrayton .

AND DESCRIPTIONS OF NEW SPECIES. 77

tooth; cavity of the beaks deep and angulated ; nacre pearly white and
iridescent.

Remarks.—This species has heretofore been considered as the Ver-
rucosus of Barnes. Although the general form resembles the Verru-
cosus, it differs from it in several essential characters. It has not the
beautiful recurved, and finely undulated beaks, nor has it the dark cho-
colate coloured nacre of the true Verrucosus. It has alarge interrupted
ray across the centre of the disk, which is absent in the other, and the tu-
berclesare more inthe form of blisters. In the Verrucosus, the first and
second growths are furnished with tubercles ; in the Pustulosus, they are
not. Objections may be made to the use of colour of nacre as a character.
It may be safely used, when on examination of many specimens, there is
no appearance of fading away by tintsinto another colour. ‘The U. for-
sus (Rafinesque) presents us always with a rich chocolate nacre. ‘The
U. rectus (Lam.) varies from rich purple and salmon through all the
tints of these colours to perfect white, and the same may be said of
the U. cuneatus (Barnes) and U. complanatus (Mya complanata,S olan. ).
The U. circulus (Nob.) varies from perfect white to dark pink. These
variations of colours are frequent in this genus. Of the numerous spe-
cimens of Verrucosus, I have never seen one which was not chocolate
coloured. In the Pustulosus, I have never seen the nacre other than
white.

Unto Stares. Plate VII. fig. 8.

Testa triangulari, subequilaterali, postice valde angulata, tuberculaté; valvu-
lis crassis; dentibus cardinalibus subgrandibus; lateralibus brevibus, a cardinalibus
separatis ; et versus baseos marginem vergentibus; margarita alba.

Shell triangular, nearly equilateral, very angular behind, tuberculated; valves
thick ; cardinal teeth rather large; lateral teeth short, distinct from the cardinal
teeth and pointing to the basal margin; nacre pearly white.

Hab. Alabama river, Judge Tait.
Vou. IV.—U

78 OBSERVATIONS ON NAIADES,

My Cabinet.

Diam. :9, Length 1:5, Breadth 1:6 inches.

Shell triangular, nearly equilateral, very angular behind, and round-
ed before; anterior portion furnished with triangular formed tuber-
cles, the apices of which point to basal margin; portion immediately be-
fore umbonial slope free from tubercles; umbonial slope elevated and
tuberculated from the beaks to the margin; posterior slope truncate,
undulated, nearly perpendicular, flat, with the exception of a small
portion of the margin behind the ligament; umbones flattened; sub-
stance of the shell thick; beaks prominent; ligament short and thick ;
epidermis yellow, .slightly wrinkled, and furnished with indistinct,
small, green pencil marks in the place of rays; cardinal tooth rather
large, elevated and widely cleft in the left valve, single and emerging
from a pit in the right valve; lateral teeth very short, straight and
pointing to the basal margin; the cardinal and lateral teeth are sepa-
rated by a flat plate; posterior and anterior cicatrices both distinct,
the smaller posterior one being placed directly over the larger, and be-
neath the point of the lateral tooth; dorsal cicatrices situated on the
under part of the cardinal tooth; cavity of the beaks deep and angula-
ted; nacre very pearly and iridescent.

Remarks.—This very curious and interesting shell was among the
many fine specimens sent me by Judge Tait, to whose kindness I am
under great obligations for several of the new species here described.
The present species, in outline, is an anomaly in the family Naiades.
The truncature behind is almost as abrupt as that of any Donaz.
This truncature gives the shell the form of a stirrup, and causes the
lateral teeth to take a direction (towards the basal margin) peculiar to
this species. The triangular form of the tubercles, particularly on the
superior anterior part, is so peculiar as to render it impossible to confound
it with any other species.

AND DESCRIPTIONS OF NEW SPECIES. 79

Unto Pustuxatus. Plate VII. fig. 9.

Testa suborbiculari, equilaterali, inflata, margine posteriori emarginata; valvulis
erassis, et duabus tuberculorum seriebus instructis ; dentibus cardinalibus magnis;
lateralibus brevibus subreclisque; margarita alba et iridescente.

Shell nearly circular, equilateral, inflated, posteriorly emarginate; valves thick
and furnished with two rows of tubercles; cardinal teeth large ; lateral teeth short
and nearly straight; nacre pearly white and iridescent.

Ohio, T. G. Lea.
Tennessee, Professor Vanuxem.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam. 1:3, Length 1-9, Breadth 2-1 inches.

Shell nearly circular, equilateral, inflated, posteriorly emarginate,
furnished with two vertical rows of tubercles on each valve, one in a
direct line from the beaks to the basal margin, the other along the um-
bonial slope ; those of the latter resemble pustules. The first tubercle
appears on the third growth; the fourth and each successive growth have
two parallel toeach other. Posterior margin granulate ; substance of the
shell thick ; beaks elevated, slightly recurved, and granulate at the tip ;
ligament short and thick ; epidermis yellowish brown and rather smooth;
cardinal tooth large, elevated and widely cleft in the left valve, single and
emerging from a pit in the right valve; lateral teeth short and nearly
straight ; anterior cicatrices distinct; posterior cicatrices confluent; dor-
sal cicatrices situated on the under part of the cardinal tooth; cavity
of the beaks deep and angulated; nacre pearly white and iridescent.

Hab. 3

Remarks.—This species somewhat resembles the U. verrucosus
(Barnes), Var. b, erected into a new species in this paper under the
name of pustulosus. It differs in being more transverse and in being
destitute of the broad single ray which passes from the beak of the
latter. Inthe arrangement of the tubercles it is altogether different ;

80 OBSERVATIONS ON NAIADES,

the pustulatus having a row, which resembles the cornutus in regularity.
These elevations however in the cornutus alternate in the two
valves, while in this species they are antagonist. In very perfect
young specimens, a minute tubercle may sometimes be observed on
the first growth. The elevations along the umbonial slope have more
resemblance to pustules, than those of the anterior row.

Unio Lens. Plate VIII. fig. 10.

Testa lenticulari, subventricosa, equilaterali; valvulis subcrassis; dentibus cardi-
nalibus magnis; lateralibus brevibus subrectisque ; margarita alba, raro rosed.

Shell lenticular, subventricose, equilateral; valves somewhat thick ; cardinal teeth
large ; lateral teeth short and nearly straight ; nacre white, rarely rose coloured.

Hab ape TG. Lea.
* 2 Tennessee, Professor Vanuxem.
My Cabinet.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of H. C. Carey.
Diam. -6, Length -9, Breadth 1-2 inches.
Shell lenticular, somewhat ventricose, equilateral; substance of the
shell rather thick ; beaks slightly prominent, undulated at tip; ligament
_short and thick; epidermis smooth, anterior to the umbonial slope
brown, posterior yellowish; cardinal teeth large and oblique, deeply
cleft in the left valve; lateral teeth short and nearly straight, in the
left valve the superior division is much the smallest; anterior cicatri-
ces distinct ; posterior cicatrices confluent ; dorsal cicatrices situated
on the under part of the cardinal tooth; cavity of the beaks angular

and somewhat deep ; nacre white, pearly and iridescent, sometimes rose
coloured.

Remarks.—This species very closely resembles the U. circulus

PL.VIM Vol.4.

Unio lens

Unio anadontordes .

Drawn by J.Drayton

—

AND DESCRIPTIONS OF NEW SPECIES. 8i

(Nob.). Itdiffersfrom it, however, in being less ventricose, in having
the beaks less elevated, in being usually more transverse, and in having
a paler brown colour. In the eireulus, the line of division of the brown
and yellow is more distinct. In the /ens, the brown is sometimes re-
placed, over the whole surface, by yellow.

Unio Anopontorpes. Plate VIII. fig. 11.

Testa angusto elliptica, transversa, inequilaterali, inflata; valvulis subcrassis ;
natibus prominulis ; dentibus cardinalibus in valvulis ambabus duplicibus et valde
erectis ; dentibus lateralibus longis, a cardinalibus separatis, subcurvatis ; marga-
rita alba et colore salmonis parum tincta.

Shell narrow- elliptical, transverse, inequilatera!, inflated ; valves somewhat thick ;
beaks slightly prominent; cardinal teeth double in both valves and very. erect;
lateral teeth long, slightly curved and separate from the cardinal teeth; nacre pale
salmon and white.

Mississippi river, T’. W. Robeson.
Hab. <~ Alabama river, Judge Tait.
Ohio river, T. H. Taylor.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Professor Vanuxem.
Cabinet of Dr Hildreth, Marietta, Ohio.
Diam. 1:5, Length 1-9, Breadth 4-1 inches.
Shell narrow-elliptical, much inflated, sometimes almost cylindrical ;
substance of the shell somewhat thick; beaks slightly prominent,
placed near the anterior margin ; ligament long, narrow, and nearly
straight; epidermis yellowish, very smooth, shining, posterior to
the umbonial slope fuscous, rarely rayed ; cardinal tooth double in
both valves, compressed, elevated; lateral teeth lamellar, very long,
slightly curved and separated from the cardinal teeth by the absence
of a plate ; anterior cicatrices distinct ; posterior cicatrices confluent;
dorsal cicatrices situated across the cavity of the beaks; cavity of the
beaks rounded, and not deep; nacre salmon or white and iridescent.
Vou. IV.—V

82 OBSERVATIONS ON NAIADES,

Remarks.—This singularly formed Unio resembles in its exterior
an Anodonta, having a remarkably smooth epidermis and possessing
in some degree the exterior of the 2. cataracta (Say). It is easily
distinguished from any described species. In some specimens the ar-
cuation of the basal margin is so great that it might almost be taken
for a malformation.

Unio Guans.. Plate VIII. fig. 12.

Testa ovato-elliptica, transversa, inequilaterali, inflata ; valvulis crassis ; denti-
bus cardinalibus subgrandibus et elevatis, lateralibus, laminatis rectisque ; marga-
ritd purpurea.

Shell ovate-elliptical, transverse, inequilateral, inflated ; valves thick ; cardinal
teeth rather large, elevated ; lateral teeth straight and lamelliform ; nacre purple.

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of S. W. Conrad.

Diam. :7, Length -8, Breadth 1-3 inches.

Shell ovate-elliptical, transverse, inflated ; substance of the shell
rather thick ; beaks somewhat prominent; ligament small; epidermis
black, or dark brown, and sometimes rayed ; cardinal teeth rather large
and elevated, in the left valve double and obliquely and deeply cleft, in
the right single, three sided, and pointed ; lateral teeth straight and lamel-
liform ; anterior cicatrices distinct ; posterior cicatrices confluent ; dorsal
cicatrices in the centre of the cavity of the beaks; cavity of the beaks
wide and subangulated; nacre purple, except along the anterior and
basal margins.

Remarks.—Although this small shell has no strikingly peculiar
character, it is nevertheless of a different species from any I have seen.
In form, it has more resemblance to U. zigzag (Nob.), than to any
other species, but differs altogether in the epidermis and nacre, being
generally destitute of rays, and having a purple nacre.

TONS ADS AYGilha fie 3

14.

Tnio ebenus-
Onw elegans

Drawn by J Drayton :

a cheniu.s
Umo elegans

Drawn by J Drayton

AND DESCRIPTIONS OF NEW SPECIES. 83

Unio Exzcans. Plate IX. fig. 13.

Testa subtriangulari, subequilaterali, per umbones complanaté ; latere antico
valvularum crassiori ; epidermide luteo-viridi ; radiis numerosis ex lineis angulatis
compositis ; natibus complanatis incurvisque ; dentibus cardinalibus elatis grandi-
busque, lateralibus subrectis ; margarita alba et iridescente, raro rosed.

Shell subtriangular, nearly equilateral, flattened over the umbones; valves thick
before, thinner behind; epidermis yellowish green with numerous rays formed of
zigzag lines; beaks incurved and flattened; cardinal teeth large and elevated ;
lateral teeth nearly straight; nacre pearly white and iridescent, rarely rose co-
loured.

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of Prof. Vanuxem.
Cabinet of H. C. Carey.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of the American Philosophical Society.
Diam. 1, Length 1-5, Breadth 1-9 inches.
Shell subtriangular, nearly equilateral, acutely angular behind ; flat-
tened over the umbones; umbonial slope carinate ; posterior slope much
flattened ; substance of the shell thick before, thinner behind; beaks
flattened, incurved, nearly touching ; ligament short and thick ; epider-
mis yellowish green, with numerous rays, formed of zigzag lines, di-
verging from the beaks to all parts of the margin; basal margin
slightly emarginate; cardinal tooth large, elevated, and widely cleft in
the left valve, and emerging from a pit in the right valve; lateral teeth
nearly straight; anterior and posterior cicatrices both distinct ; dorsal
cicatrices situated in the centre of the cavity of the beaks; cavity of
the beaks rounded ; nacre pearly white, (rarely pink) and iridescent.

Remarks.—This interesting and beautiful species has been consi-
dered as a variety of the U. donaciformis (Nob.). I had but a single

84 OBSERVATIONS ON NAIADES,

and imperfect specimen of this shell when I described the donacifor-
mis, and I presumed it to be merely a variety of that shell. Subse-
quently, my attention being drawn particularly to it, I procured some
of all the different growths, and among them the beautiful specimen
now figured, which is the only one I have seen of a pink colour. On
an examination of these, I could no longer doubt of its being distinct ;
but some doubts have arisen in my mind whether the donaciformis
may not be a variety of the U. zigzag (Nob.). The specimen des-
cribed as donaciformis is a very fine and perfect one, and if it be a true
species is the only one I have seen. Among the numerous specimens
of zigzag which I have examined, none have had those perfect and
beautifully pointed beaks of the donaciformis; should future specimens
fully establish the donaciformis, its natural place will be between the
zigzag and the present described species. ‘These observations it is
hoped will draw the attention of conchologists to this species, with
the expectation of being able, by examining many specimens, to decide
upon the question.

Unto Expenvus. Plate IX. fig. 14.

Testa subelliptica, oblique recurva, inequilaterali, ventricosa ; valvulis crassis ;
natibus prominentibus et subterminalibus ; epidermide nigro-fusca, sed posi nates
luted ; dentibus cardinalibus magnis, lateralibus magnis curvisque; margarita
alba.

Shell subelliptical, obliquely recurved, inequilateral, ventricose ; valves thick ;
beaks elevated and nearly terminal ; epidermis blackish brown, behind the beaks
yellow; cardinal teeth large; lateral teeth large and curved ; nacre pearly white.

Hab. Ohio river, 'T. G. Lea.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Diam. 1°1, Length 1-5, Breadth 1-6 inches.
Shell subelliptical, obliquely recurved, inequilateral, very ventricose ;

a

AND DESCRIPTIONS OF NEW SPECIES. 85

substance of the shell very thick; beaks nearly terminal and very
much elevated ; ligament rather short and thick; epidermis blackish
brown, behind the beaks on the second growth it is yellow; tip of the
beaks yellowish; cardinal teeth large and oblique, being in a line
nearly parallel to the lateral tooth which is thick and slightly curved ;
posterior and anterior cicatrices both distinct ; dorsal cicatrices situated
on the under side of the plate between the cardinal and lateral
teeth ; cavity of the beaks deep and angulated ; nacre pearly white and
iridescent.

Remarks.—This species, which seems to be peculiar in the yellow
mark behind the beaks, resembles the: U. mytiloides: (Rafin.) and
might easily be mistaken for a ventricose variety of that species where
the beaks are so much eroded as to have destroyed the second growth.
A young individual of second growth is represented in the plate to ex-
hibit the curious distribution of colour. The posterior third is yellow
and the remainder green, the line of separation being very distinct.
Those of three growths usually have no trace of yellow on the third
growth which takes a brown colour. The first growth, which may
be considered the tip of the beaks, is usually yellow or yellowish
green over its whole surface. The largest specimen given in the
plate is not more than one fourth the size it is sometimes found. It
is selected, because it is the largest I have seen with the beaks suffi-
ciently perfect to exhibit the peculiar yeliow colour of this part.

ees *

Unio Asper. Plate IX. fig. 15.

Testa subtriangulari, inequilaterali, postice angulatd, valde tuberculata ; valvulis
crassis; dentibus cardinalibus subgrandibus; lateralibus aliquantulum curvatis ;
margarita alba.

*
Shell subtriangular, inequilateral, angular behind, much tuberculated; valves
thick; cardinal teeth rather large ; lateral teeth slightly curved; nacre pearly white.

Hab. Alabama river, Judge Tait.
Vor. IV.—W

86& OBSERVATIONS ON NAIADES, :

My Cabinet.

Diam. -9, Length 1-4, Breadth 1°8 inches.

Shell subtriangular, angular behind and rounded before, covered
with small rough tubercles except in a furrow which passes from the
beak obliquely to the basal margin which is there arcuate; the tuber-
cles along the posterior slope arrange themselves into a series of undu-
lations as far as the beaks; substance of the shell thick; beaks slightly
prominent: ligament short and thick; epidermis brown and wrinkled ;
cardinal tooth rather large, slightly elevated and widely cleft in the
left valve, single and emerging from a pit in the right valve ; lateral
teeth small, slightly curved in a direction over the cardinal teeth; pos-
terior and anterior cicatrices. both distinct; dorsal cicatrices situated
on the under part of the cardinal tooth within the cavity; cavity of the
beaks deep and angulated ; nacre very pearly and iridescent.

Remarks.—The asper is more covered with tubercles than any spe-
cies I have seen, these being small and numerous. It bears some re-
semblance to U. fuberculatus (Barnes), and U. lacrymosus (Nobis.).
It differs from the fwherculatus in outline, and in possessing a furrow
passing from the beaks to the basal margin. It differs from the
lacrymosus in the form of the tubercles (which in that species so
much resemble flowing tears) and in the roughness and colour of the
exterior.

Unio Fanauis. Plate X. fig. 16.

Testa subelliptica, transversd, inequilaterali, crassé; valvulis crassis ; radiis
capillaribus undantibusque ; dentibus cardinalibus parvis ; lateralibus brevibus,
crassis, et in termino postico auctis; margarita alba et tridescente.

Shell subelliptical, transverse, inequilateral, thick; valves thick; rays hair-like

and undulating; cardinal teeth small; lateral teeth short, thick and enlarged towards
the posterior end; nacre pearly white and iridescent.

Hab. Ohio river, T. G. Lea.

PL.X,Vol, 4.

Cece Ker

- aS:
panos ONS

nee Tt NG: ‘

ae es ema

ington eee SS

Unie

solenvfoTrmis .

Unio fabalis
Jf

Unzo acutisstmus.

Drawn. hy 1Draayton

a

na

ii

‘een ary

he
i}

AND DESCRIPTIONS OF NEW SPECIES. 87

My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of R. E. Griffith, M.D.
Cabinet of Academy of Natural Sciences.
Diam. °3, Length -5, Breadth 1 inch.
Shell subelliptical, transverse, thick; substance of the shell thick;
beaks slightly prominent; ligament short; epidermis dark, and finely
wrinkled; rays green, hair-like, and undulating, particularly on the
posterior half; cardinal tooth double, and deeply cleft in the left
valve and single in the right; lateral teeth short, straight, thick and
enlarged towards the posterior end ; posterior and anterior cicatrices both
distinct, the smaller posterior one being placed directly over the larger
and beneath the point of the lateral tooth; dorsal cicatrices situated in
the centre of the cavity of the beaks; cavity of the beaks shallow and
arched; cavity of the shell small and irregularly undulated; nacre
pearly white and iridescent.

Remarks.—This little species first attracted my attention about
three years since, when I had seen but a single specimen. Although
a very small shell, I felt satisfied it possessed the characters of an
adult, and my curiosity being much excited in regard to it, I made
many efforts to obtain other individuals. For several of these I am
indebted to the kindness of Dr Hildreth of Marietta and to Mr Robert
Peter and J. S. Craft, Esq. of Pittsburg. The fabalis most resembles
the parvus of Barnes. It has nearly the same size and outline ; but differs
much in the thickness of the valves and in the beaks. The fwbalis is
covered with rays, the parvus has none.

Unto Sotentrormis. Plate X. fig. 17.

Testi angusto-elliptica, transversi, compressa, inequilaterali, ad finem utrum-
que rolundata ; valvulis tenuibus ; natibus prominulis ; valvuld utraque tuberculum

88 OBSERVATIONS ON NATADES,

parvum et simplicem in loco dentis cardinalis habente ; dentibus lateralibus, longis,
rectis, et valde imperfectis ; margarita ceruleo-alba et iridescente.

Shell narrow-elliptical, transverse, compressed, inequilateral, rounded at both
ends; valves thin; beaks slightly prominent; cardinal tooth a simple, small tubercle
in both valves; lateral teeth long, straight and very imperfect ; nacre bluish white
and iridescent.

Hab. Ohio, T. G. Lea.
My Cabinet.
Cabinet of Dr Hildreth, Marietta, Ohio.

Diam, 1:1, Length 1-7, Breadth 4-3 inches.

Shell narrow-elliptical, transverse, rounded at both ends, compressed
from the beaks to the basal margin over the umbones, slightly arcuated
on the basal margin; posterior margin much compressed, substance of
the shell thin; beaks minutely undulated, slightly prominent and
approaching the anterior margin; ligament long and thick; umbones
and inferior parts flattened ; umbonial slope rounded and elevated ; epi-
dermis very dark brown and wrinkled; cardinal tooth formed of a
simple small tubercle in both valves, larger in the right valve: lateral
teeth straight, and so imperfect as to be divided, even in the left valve,
only near the posterior end ; anterior cicatrices distinct; posterior cica-
trices confluent; dorsal cicatrices situated under the plate between the
cardinal and lateral teeth; cavity of the beaks wide and shallow.

Nacre bluish white and iridescent.

Remarks.—A single specimen of this extraordinary and highly inte-
resting shell came into my possession in 1827. The outline and teeth
presented such an anomaly, that I was induced when I published my
other memoirs on this family to lay it aside until I could better satisfy
myself in regard to it. It was a very old individual, and I feared the
peculiar characters it presented might have been produced by malfor-
mation and extreme age. After two or three years of unwearied at-
tempts, I fortunately procured from Mr T. H. Taylor of Louisville a
junior and an adult specimen, both exceedingly perfect, the latter of
which is here represented. This proteus family seems destined to perplex
the zoologist and to lead him into an inexplicable labyrinth. The pre-

AND DESCRIPTIONS OF NEW SPECIES. 89

sent species forms a natural link between Unio and Anodonta, by
means of this imperfect lateral tooth.

Unio Acurissimus. Plate X. fig. 18.

Testa angusto-elliptica, inequilaterali, postice acute angulata; undulis a clivo
umboniali divaricantibus; natibus prominulis; valvulis tenuissimis; dentibus cardi-
nalibus parvis, lateralibus longis rectisque; margarita tenuissimd, colore salmonis
tincta.

Shell narrow-elliptical, inequilateral, transverse, acutely angulated behind, with
undulations diverging from the umbonial slope ; beaks slightly prominent ; valves very
thin; cardinal teeth small; lateral teeth long and straight; nacre salmon-coloured
and very thin.

Hab. Alabama river, Judge Tait.
My Cabinet.

Diam. -4, Length -5, Breadth 1-1 inches.

Shell narrow-elliptical, transverse, acutely angulated behind, with
undulations diverging from the umbonial slope ; substance of the shell
very thin; beaks slightly prominent and placed about one third the
distance from anterior margin; ligament linear; epidermis yellow,
smooth and shining; cardinal teeth small and single in both valves;
lateral teeth long and straight; anterior cicatrices distinct; posterior
cicatrices confluent ; dorsal cicatrices within the cavity of the beaks; ca-
vity of the beaks wide and shallow, nacre salmon-coloured and very thin.

Remarks.—This minute shell, among the smallest of the species, is

most nearly allied in outline to U. anodontoides. It differs from it in
having undulations, and is totally dissimilar in point of magnitude.

Von. 1V:— x

90 OBSERVATIONS ON NAIADES,

Unto Varicosus. Plate XI. fig. 20.

Testa subelliptica, obliqua, postice compressa, varicibus transversis et concentricis
instructa ; valvulis precrassis ; natibus subterminalibus, prominentibus, incurvis ;
dentibus cardinalibus modicis; lateralibus longis,magnis et subrectis; margarita alba.

Shell subelliptical, oblique, compressed behind, varicose, with transverse concentric
elevations; valves very thick; beaks nearly terminal, elevated, incurved ; cardinal
teeth rather small ; lateral teeth long, large and nearly straight ; nacre pearly white.

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of Prof. Vanuxem.
Cabinet of P. H. Nicklin.
Diam. 2:1, Length 3, Breadth 4-2 inches.
Shell subelliptical, oblique, compressed and rounded behind, varicose
from near the beak to basal margin, with transverse concentric eleva-
tions along the lines of successive growth; substance of the shell very
thick; beaks nearly terminal, elevated, incurved; ligament long and
large ; epidermis reddish brown; cardinal tooth rather small, direction
same as lateral tooth, widely cleft in the left valve, in the right valve
emerging from a pit; lateral teeth long, large and nearly straight; an-
terior and posterior cicatrices both distinct; dorsal cicatrices situated
on the lower part of the cardinal tooth, and on the under side of the
plate between the cardinal and lateral teeth ; cavity of the beaks rather
deep and rounded ; nacre pearly white.

Remarks.—This species most resembles the U. sopus (Green). It
differs from it, however, in being rounded behind, in the beaks being
nearly terminal, in the varices being less elevated and more trans-
verse; and in the absence of elevations along the umbonial slope.
There being no varicose undulations on young individuals, which are
generally obscurely radiated, it is difficult for the unpractised eye to
recognize the species to which they belong.

PAs.. XE SVol A

Unio vartcosus

Symphaynota bilovwate .

Unio castaneus
Drawn ty I Drorepter,

(Tino

niublistreatus

Drawn by ),Lrayton

lal,

Uno

XIT Vol

decisws

4

Unto cu 1 PUPILS:

AND DESCRIPTIONS OF NEW SPECIES. 91

Unto Castanevs. Plate XI. fig. 21.

Testa subellipticd, inequilaterali, obliqua, inflata; valvulis crassis; dentibus car-
dinalibus magnis; lateralibus subrectis brevibusque; margarita maxime fulgente et
iridescente.

Shell subelliptical, inequilateral, oblique, inflated; valves thick; cardinal teeth
large; lateral teeth nearly straight and short; nacre very pearly and iridescent.

Hab. Alabama river, Judge Tait.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.

Diam. °6, Length °8, Breadth 1 inch.

Sheil subelliptical, oblique ; substance of the shell thick; beaks pro-
minent and situated towards the anterior margin; ligament short; epi-
dermis slightly wrinkled, dark brown anterior to the umbonial slope,
and yellowish posterior, where there are a few obsolete rays; cardinal
tooth large, slightly elevated, deeply cleft in the left valve and emerg- _
ing from a pit in the right valve; lateral teeth short and nearly
straight; posterior and anterior cicatrices both distinct ; dorsal cicatrices
situated on the under part of the cardinal tooth within the cavity ; cavity
of the beaks wide and shallow; nacre very pearly and iridescent.

Remarks.—This small species is allied to the U. circulus (Nob.)
in colour and to U. ellipsis (Nob.) in form. It has the posterior slope
yellow, which is so in the circulus. The specimen described and
figured here is not more than one fourth of the size of an imperfect
specimen which accompanied it.

Unio Muxtistriatus. Plate XII. fig. 22.

Testa striata, transversd, inequilaterali; natibus prominulis; umbonibus rugo-
sis; dente cardinali obliquo, laminato, in valvula sinistré unico, in dextré duplici;
dente laterali longo et subrecto; margarita ceruleo-alba.

92 OBSERVATIONS ON NAIADES, ®

Shell striate, transverse, inequilateral; valves thin; beaks slightly prominent ; um-
bones rugose; cardinal tooth oblique, lamelliform, single in the left valve and dou-
ble in the right; lateral tooth long and nearly straight; nacre bluish white.

Hab. Brazil, Mrs Mawe.
My Cabinet.

Diam. 7, Length 1, Breadth 1-9 inches.

Shell subrectangular, transverse, slightly compressed and rounded
nearly alike at both ends; substance of the shell rather thin; beaks
slightly prominent, surrounded by wrinkles forming acute angles with
each other, extending over the umbones and some distance down the
umbonial slope ; ligament. linear; epidermis dark brown and wrinkled ;
cardinal tooth oblique, lamelliform, single in the left valve and double
in the right; lateral teeth long, lamelliform and nearly straight ; anterior
and posterior cicatrices both confluent; dorsal cicatrices in the centre of
the cavity of the beaks; cavity of the beaks wide and shallow ; nacre
bluish white and slightly iridescent in posterior margin.

Remarks.—The specimen from which the above description was made
--was sent to me by Mrs Mawe of London. 'This species approaches
in outline to some of the varieties of the U. complanatus (Solan.). In
the flexuous rugosities of the beaks it resembles the U. corrugatus
(Lam.) and U. cxruleus (Nob.). It differs however from them both
in outline.

Unio Decisus. Plate XII. fig. 23.

Testa inequilaterali, obliqua, cuneaté, scalend, crassdque; valvulis percrassis; na-
tibus elevatis, incurvatis, fere terminalibus; dentibus cardinalibus aliquantulum par-
vis, lateralibus crassis; margarita alba.

Shell inequilateral, oblique, wedge shaped, scaleniform and thick; valves very

thick; beaks elevated, incurved, nearly terminal ; cardinal teeth rather small; lateral
teeth thick ; nacre pearly white.

Hab. Alabama river, Judge Tait.

AND DESCRIPTIONS OF NEW SPECIES. 93

My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of H. C. Carey.
Cabinet of P. H. Nicklin.
Cabinet of the American Philosophical Society.

Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of the Lyceum of Natural History of New York.
Diam, 1-4, Length 1-7, Breadth 3-2 inches.

Shell wedge-shaped, thick anteriorly and scaleniform; substance of
the shell thick anteriorly and thin posteriorly; beaks nearly terminal,
prominent and incurved, generally decorticated; ligament rather
small; epidermis yellowish brown, sometimes possessing oblique, in-
distinct, brown rays; cardinal tooth short and slightly elevated, in the
left valve double and deeply cleft, in the right valve emerging from a
pit; lateral teeth thick and curving over the cardinal teeth; posterior
and anterior cicatrices both distinct; the smaller posterior cicatrix sit-
uated against the lateral tooth at its termination; dorsal cicatrices sit-
uated on the under part of the cardinal tooth; cavity of the beaks not
deep, rounded; nacre thick and pearly anteriorly, thin and iridescent
posteriorly.

Remarks.—This species resembles the sealenia of Rafinesque, but
more closely approaches the pafulus (Nob.) and truncatus* (Swain-
son). It differs from the patulus in the rays being uninterrupted, and
in being much thicker. From the fruncatus it differs greatly in the
cardinal tooth and in being wedge shaped and not cylindrical.

* J will take advantage of this opportunity to correct an error, in stating in a former pa-
per that Lamarck and other European conchologists erroneously made the genus Unio femi-
nine. I should then have mentioned that Mr Swainson was an exception.

Vou. IV.—Y

94 OBSERVATIONS ON NAIADES,

Unto Currinus. Plate XII. fig. 24.

Testé ovata, transversa, inequilaterali, inflata, postico latere latissimo; valvulis
tenuibus; natibus parvis undulatisque; dentibus cardinalibus exiguis, lateralibus
laminatis; ligamento longo; margarita cupreda.

Shell reversely ovate, transverse, inequilateral, inflated; valves thin; beaks small
and undulated; cardinal teeth small; lateral teeth thin and lamellar; ligament long;
nacre copper colour.

Hab. Mexico, J. R. Poinsett, Esq.
My Cabinet.
Cabinet of the American Philosophical Society.

Diam. -9, Length 1-1, Breadth 2°1 inches.

Shell reversely ovate, transverse, inflated, disposed to be straight in
the basal margin; substance of the shell thin; beaks small, pointed,
furnished with concentric undulations and placed near the anterior
margin; ligament long, lanceolate; umbonial slope large and rounded ;
posterior slope elevated into a carina; epidermis reddish brown and
wrinkled ; rays obsolete; cardinal teeth very small and tuberculated ;
lateral teeth slender, lamellar and nearly straight; anterior and poste-
rior cicatrices both confluent; dorsal cicatrices in the centre of the
cavity of the beaks; cavity of the beaks wide ; nacre copper colour and
very brilliant towards the posterior margin.

Remarks.—This remarkable shell is one of the many fine specimens
of the splendid collection of interesting subjects brought by our fellow
member J. R. Poinsett, Esq. from Mexico, and which, by his munifi-
cence, now constitutes a valuable part of the collection of this society.
In comparing this species with the others of the genus, we shall find
it most to resemble the complanatus (Solan.).. It differs however in
having the posterior dorsal margin more elevated, in the peculiar cop-
per colour of the nacre, and in the concentric undulatiens of the beaks.
In the specimens which I have had an opportunity of examining, the
anterior cicatrices were found to be confluent, a circumstance rarely
met with in the Uniones.

oa

PL, .XIM,Vol. 4

5
Unto obesies,

Trio cerwleus,

Unio treurmes ,

Drow Ty I Drayton,

AND DESCRIPTIONS OF NEW SPECIES. 95

Unio Czrutevs. Plate XIII. fig. 25.

Testa angusto-elliptica, transversd, inequilaterali, subcylindracea; valvulis ten-
uibus; natibus prominulis, rotundatis et undulatis; dentibus cardinalibus lamelli-
Formibus, et in dextra valvula sola duplicibus; lateralibus rectis; margarita ceru-
leo-alba et iridescente. :

Shell narrow-elliptical, transverse, inequilateral, subcylindrical; valves thin ; beaks
rather elevated, rounded and undulated; cardinal teeth lamelliform and double in
the right valve only; lateral teeth straight ; nacre bluish white, pearly and irides-
cent.

Hab. River Hoogly, Hindostan, G. W. Blakie.
My Cabinet.
Cabinet of G. W. Blakie.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of H. C. Carey.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Cabinet of Dr Burrough.

Diam. -6, Length ‘8, Breadth 1-6 inches.
Shell narrow-elliptical, transverse, subcylindrical, disposed to be

straight on the sides and basal margin ; substance of the shell thin ; beaks
near the anterior margin rounded, somewhat elevated, and corrugated
with diverging undulations; ligament rather short and straight; epi-
dermis finely wrinkled and bluish green, particularly on the posterior
part; rays very indistinct; posterior slope furnished with small undu-
lations and two irregular rays on each side; cardinal teeth lamelliform
and double in the right valve only; lateral teeth straight and lamelli-
form; anterior cicatrices distinct ; posterior cicatrices confluent; dor-
sal cicatrices within the cavity of the beaks; cavity of the beaks
wide and rounded; nacre bluish white, very pearly and iridescent.

Remarks.—This species was brought from Calcutta by Mr Blakie,
to whose kindness I am indebted for it and many other fine shells.

96 OBSERVATIONS ON NAIADES,

As far as I have been able to ascertain, it has not been described.
From the roughness of the beaks it might perhaps be thought to
be only a variety of corrugata (Lam.). On comparing the two spe-
cies, however, they will be found to be entirely distinct; the corru-
gata being “ovato-rhombea,” while the cxruleus is “angusto-ellip-
tica.” In some specimens the nacre is slightly rose-coloured along the
basal margin.

Unio Osesvs. Plate XIII. fig. 26.

Testa rhomboides-ovata, obliqud, inequilaterali, inflata; valvulis subcrassis; na-
tibus prominulis; dentibus cardinalibus elevatis, compressis cristatisque; lateralibus
longis et curvatis; margarita livido-alba.

Shell ovate-rhomboidal, oblique, inequilateral, inflated; valves somewhat thick;
beaks rather prominent; cardinal teeth elevated. compressed and crested; lateral
teeth long and curved; nacre livid white.

Hab. York river, Vir., William Cooper.
My Cabinet.
Cabinet of Lyceum of Natural History of New York.
Diam. 1:5, Length 2, Breadth 3-3 inches.
Shell ovate-rhomboidal, oblique, inflated, angular behind; substance
of the shell somewhat thick ; beaks rather prominent and placed near
the anterior margin; posterior slope wide and furnished with two im-
pressed lines on each side; ligament long and large; epidermis fuscous
and much wrinkled ; rays obsolete; cardinal teeth oblique, elevated,
lamellar, crested, deeply cleft in the left valve; lateral teeth long,
curved and enlarged towards the posterior termination; anterior cica-
trices distinct ; posterior cicatrices disposed to be distinct; dorsal cica-
trices form a row across the cavity of the beaks; cavity of the beaks
rounded and deep; nacre livid white and iridescent on the posterior
margin.

Remarks.—This is one of the specimens so disinterestedly contri-
buted to our Transactions by the Lyceum of Natural History of New

AND DESCRIPTIONS OF NEW SPECIES. 97

York. Its natural situation seems to be between the cariosus (Say),
and complanatus (Solan.). It has the capaciousness of the former, and
somewhat of the outline of the latter.

Unto Incurvus. Plate XIII. fig. 27.

Testé ovato-rhombea, transversd, inequilaterali; valvulis antice crassis, postice
tenuibus; natibus rugosis, prominentibus incurvisque; dentibus cardinalibus ele-
vatis cristatisque, lateralibus longis et subcurvis; margarita alba et iridescente.

Shell ovate-rhomboidal, transverse, inequilateral ; valves thick anteriorly and thin
posteriorly; beaks rugose, prominent and incurved; cardinal teeth elevated and
crested; lateral teeth long and slightly curved; nacre pearly white and iridescent.

Hab. ***. From Gibraltar, Mrs Mawe.
My Cabinet.

Diam. 1, Length 1-4, Breadth 2.1 inches.

Shell ovate-rhomboidal, transverse, slightly inflated; substance of
the shell thick and white anteriorly, thin and iridescent posteriorly ;
beaks prominent, large, incurved and rugose, with small concentric un-
dulations : ligament rather short and thick ; epidermis yellowish brown ;
rays oblique and green; cardinal tooth elevated, crested and divided in
the left valve, in the right simple and recurved; lateral tooth long,
slightly curved and enlarged at posterior termination; anterior cica-
trices distinct; posterior cicatrices confluent; dorsal cicatrices situated
on the under part of the cardinal tooth; cavity of the beaks wide and
angulated ; nacre white on the anterior, and iridescent on the posterior
portion.

Remarks.—This shell, although it possesses no very striking char-
acter, cannot be placed with any American or exotic described species
with which I am acquainted. It was sent to me by Mrs Mawe with
the locality “from Gibraltar” on the label, and I have little doubt but
that it came from some neighbouring African river. It certainly does

not belong to any described European species. It bears more resem-
Vou. IV.—Z

98 OBSERVATIONS ON NAIADES,

blance to the corrugata, Var. a (Lam.), than to any other species I
have seen. It differs, however, in being more transverse, in the beaks
being more prominent, and in their rugosities being composed of con-
centric undulations.

Sympnynora Buweata. Plate XI. fig. 19.

Testa subellipticé, transversd, inequilaterali, compressa; valvulis tenuissimis;
posteriori. margine dorsali elevati connataque; natibus subprominulis, undulas
concentricas e€ duas lineas elevatas ad marginem posteriorem currentes, habentibus;
dentibus cardinalibus laminatis et in valvula dextra solum duplicibus; lateralibus
rectis; margarita colore salmonis subtincta.

Shell subelliptical, transverse, inequilateral, compressed; valves very thin, poste-
rior dorsal margin elevated and connate; beaks very slightly elevated, concentri-
cally undulate and possessing two elevated lines which pass to the posterior margin ;
cardinal teeth lamelliform and double in the right valve only; lateral teeth straight;
nacre slightly salmon coloured.

Hab. River Hoogly, Hindostan, G. W. Blakie.
My Cabinet.
Cabinet of G. W. Blakie.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences.
Diam. °3, Length -7, Breadth 1-3 inches.
Shell subelliptical, transverse, inequilateral, compressed, diaphanous ;
substance of the shell extremely thin; beaks very slightly elevated,
concentrically undulate, possessing two small elevated lines which
pass (posterior to the umbonial slope) to the posterior margin; valves
elevated into a carina and connate in the posterior dorsal margin ; dor-
sal margin a right line; ligament very small; epidermis shining, green-
ish yellow, darker on the posterior slope; cardinal teeth lamelliform
and double in the right valve only; lateral teeth lamelliform, long
and straight ; posterior and anterior cicatrices both confluent; dorsal
cicatrices obsolete; cavity of the beaks shallow, very wide, and

PL. //. Wol.A.
Hf

Symphynota inflata.

Drawn by J.Draytan »

AND DESCRIPTIONS OF NEW SPECIES. 99

exhibiting the undulations of the beaks; nacre very thin and slightly
salmon coloured, darker in the cavity of the beaks.

Remarks.—This very small species was brought from Calcutta by
Mr Blakie, with the U. ceruleus (Nob.). Both were procured about
one hundred miles above that city. It resembles, in its outward char-
acters, the young of S. cygnea (Anod. cygnea, authors). It is, how-
ever, more transverse, and differs altogether in the formation of the
hinge, which is furnished with perfect cardinal and lateral teeth. In
the peculiar character of the double tooth in the right valve, it resem-
bles the S. ochracea.* The bilineata is easily distinguished by the
two delicate lines which pass from the beaks to the posterior margin.

SympnHynoTa Inruata. Plate XIV. fig. 28.

Testa ovato-triangulari, inequilaterali, ventricosa; valvulis pertenuibus, connato-
bialatis; dente cardinali in valvula singuld unico; dentibus lateralibus ad terminos
laminatis; natibus prominulis; ligamento celato; margarita purpurea.

Shell triangular-ovate, inequilateral, ventricose ; valves very thin, elevated into two
wings, both of which are connate ; cardinal tooth single in both valves ; lateral teeth
bladed towards their termination; beaks slightly prominent; ligament concealed ;
nacre purple.

Hab. Alabama river, Judge Tait.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of the Academy of Natural Sciences.

Diam. 1-6, Length from the beaks to the base, 2-4, Breadth 4:5 inches.
Length from the top of the wing to the base, 3-7 inches.

Shell triangular-ovate, ventricose, transversely and finely wrinkled ;
substance of the shell thin; valves elevated into a broad high wing pos-
terior, and a small one anterior to the beaks, and connate in both ; pos-

* See vol. ili. p. 455.

100 OBSERVATIONS ON NAIADES,

terior wing recurved at top; beaks slightly prominent; ligament con-
cealed in the wing; epidermis brown, with obsolete rays; two or three
fuscous lines pass from the beak to the posterior margin above the um-
bonial slope; cardinal tooth single in both valves, and lamelliform ;
lateral teeth bladed and elevated towards their termination; the two
teeth form one continuous curve line (with the exception of a slight
angle where they join) which is abrupt at both ends; anterior cicatri-
ces distinct; posterior cicatrices confluent; dorsal cicatrices pass from
the cavity towards the anterior cicatrices, and are very perceptible ;
cavity of the beaks wide and shallow; nacre purple and iridescent.

Remarks.—I am indebted, for this fine shell, to Judge Tait of Ala-
bama, who kindly sent it to me with several other new species of fluvi-
atile and terrestrial shells described in this paper. This species seems to
form’a natural link between S. /evissima (Nob.) and S. bialata (Nob.).
It resembles the former in colour and in the teeth, but differs in the
elevation of the wing, and in being less shining and more ventricose. It
resembles the latter in its elevated wing and general outline, but dif-
fers from it in nacre, exterior colour, in net being possessed of undu-
lations along the base of the posterior wing, and in the teeth.

Mewanra Suputaris. Plate XV. fig. 30.

Testa elevata, turrita, corned; apice acuto; anfractibus instar duodenis, planis;
anfractu infimo in medio carinato; apertura alba, quadrante longitudinis testa.

Shell elevated and acutely turrited, horn colour ; apex acute ; whirls about twelve,
flat, carinate on the middle of the body whirl; base angulated; aperture white and
one-fourth the length of the shell.

Hab. Niagara river.
My Cabinet.
Diam. -4, Length 1-3 inches.

Remarks.—I took this species at the Falls of Niagara, and being un-

. Melania elongata 5

at;
eA

subularis .

tubereulala

iY !

PLAV. Vat. 4.

tos
pS

Melania acuta .
Uchex carolininsis

Carocolla helicotdes .

Carecolla spinosa :
Valvata ANY

Jo yistjormis -
jbeiel?

AND DESCRIPTIONS OF NEW SPECIES. 101

able to refer it to any described species, have given it a place here.
It resembles the virginica (Say), but differs greatly in elevation, the
virginica having about seven whirls only. The carina causes the
whirls to be flatterin the subularis, In some specimens the columella
is purple.

Metanta Tupercunata. Plate XV. fig. 31, a, b.

Testa obtuse turrita, lata, tenebroso-fuscd aut nigrante; apice obtuso; anfractibus
quinque; medio anfractus ultimi tuberculis instructo; labro enormiter curvo; basi
angulata; apertura purpured, dimidium longitudinis teste habente.

Shell obtusely turrited, wide, very dark brown or black; apex obtuse ; whirls five ;
middle of the last whirl furnished with tubercles ; outer lip irregularly curved ; base
angulated ; aperture purple and one half the Jength of the shell.

Hab. Tennessee river, Professor Vanuxem,
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Cabinet of Academy of Natural Sciences.
Diam. °5, Length -9, of an inch.

Remarks.—This species is somewhat allied to the M. armigera
(Say), but is smaller and much less ponderous. The tubercles are more
numerous and less elevated. In the fwberculafa the impressed band,
which exists in the armigera above the armature, is wanting. In co-
lour it differs altogether,

Mexania Acura. Plate XV. fig. 32.

Testa acute turrita, tenui, corned; apice acuto; anfractibus octo, supra suturam
carinatis, in longum undatis, transversim lineatis; basi angulatd; apertura alba,
quadrantem longitudinis teste habente.

Vou. IV.—2 A

102 OBSERVATIONS ON NAIADES,

Shell acutely turrited, thin, horn-ccloured ; apex acute ; whirls eight, carinate im-
mediately above the suture, longitudinally undulated and transversely lineated ; base
angulated ; aperture white, and one-fourth the length of the shell.

Hab. Tennessee river, Professor Vanuxem.
My Cabinet.
Cabinet of Prof. Vanuxem.
Diam. five-twentieths, Length thirteen-twentieths of an inch.

Remarks.—I have seen no described species to which this bears a
close resemblance. Its delicate form, furnished with undulations and
transverse lines, will easily distinguish it.

Hewix Caroutnrensis. Plate XV. fig. 33, a, b, c.

Testa supra depressa, infra inflata, oblique striata, fusca, imperforata; anfracti-
bus quinque; spira maxime obtusa; apertura coarctata; labro albo, reflexo, latoque,
duobus dentibus instructo, quorum inferior longus et laminatus, superior parvus et
conicus est; columella dentem levatum incurvumque habente; columelle basi valde
impressa.

Shell depressed above, inflated below, obliquely striated, fuscous, imperforate ;
whirls five; spire very obtuse; aperture contracted ; outer lip white, broad and re-
flected, furnished with two teeth, the inferior one long and lamellar, the superior
one small and conical ; columella with an elevated incurved tooth ; base of the co-
lumella much impressed.

Hab. South Carolina near Cheraw.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. fourteen-twentieths, Length seven-twentieths of an inch.

Remarks.—I found a few specimens of this fine Helix while travel-
ling through South Carolina three years since. ‘They were taken from
beneath the bark of an old tree. It is closely allied to Mr Say’s pal-

AND DESCRIPTIONS OF NEW SPECIES. 10%

hata, but differs in the region of the base of the columella being more
deeply impressed. The oblique strie are more distinct, and no speci-
men which I obtained is in the least hirsute.

Carocouita Henicormwes. Plate XV. fig. 34, a, b, ¢.

Testa orbiculata, fusca, supra plano convexa, subtus inflata, imperforata, oblique
striata; anfractibus quinque; spira obtusissima; apertura contracta; labro albo, lato
et refleco, dentibus duobus instructo, quorum inferior longus et laminatus, superior
parvus et conicus est; columella dentem unicum, longum, elevatum et incurvum
habente.

Shell orbicular, fuscous, plano-convex above, inflated below, imperforate, ob-
liquely striated; whirls five ; spire very obtuse ; aperture contracted ; outer lip white,
broad, and reflected, furnished with two teeth, the inferior one long and lamellar,
the superior one smail and conical ; columella with a long, elevated, incurved tooth.

Hab. Tennessee, near Nashville, Professor Vanuxem.
My Cabinet.
Cabinet of Professor Vanuxem.
Helix palliata? Say, Var. a, Academy of Natural Sciences, Vol. II,
p. 152.
Diam. eighteen-twentieths, Length nine-twentieths of an inch.

Remarks.—Among the fine shells brought by Professor Vanuxem
some years since from a tour through the Western states were two
specimens of this beautiful Carocolla. In its specific characters it resem-
bles the Helix palliata of Say, and Helix caroliniensis described in this
paper. It is destitute of the hirsute appearance of the palliata, and is
entirely distinct in the flatness of the whirls of the spire. In the ca-
roliniensis the base of the columella is more impressed and the whirls
more inflated.

104 OBSERVATIONS ON NAIADES,

Carocotua Spinosa. Plate XV. fig. 35, a, b, ¢.

Testa lenticulari, tenui, pellucida, imperforata; caring acuta ef spinis minutis mu-
nitd; anfractibus sex; spira fere plana; apertura angustissima; columella den-
tem unicum longum et laminatum habente; labro enormiter crasso et prope finem
superiorem angulato.

Shell lenticular, thin, diaphanous, imperforate ; carina acute and armed with
minute spines ; whirls six; spire nearly planular ; aperture linear, being guarded by
a long tooth on the columella; cuter lip irregularly thick, angulated near the supe-
rior termination.

Hab. Alabama near Clairborne, Judge Tait.
My Cabinet.
Cabinet of the Academy of Natural Sciences.
Diam. eleven-twentieths, Length four-twentieths of an inch.

Remarks.—F¥or this beautiful and highly interesting species I am
indebted to the kindness of Judge Tait. Its peculiar delicate spines
distinguished it from all described species. 'These, however, when the
specimens are not perfect, are entirely obliterated. In the construction
of the aperture it is unlike every Carocolla I have seen, bearing much
resemblance in this region to the Helix hirsuta (Say).

VatvaTa ArenrreRA. Plate XV. fig. 36, a, b.

Testa orbiculata, convexa; anfractibus tribus, qui arenis agglutinatis operiuntur;
umbilico lato; spira obtusa.

Shell orbicular, convex ; whirls three, covered by the agglutinations of sand ; um-
bilicus wide ; spire obtuse.

Hab. Cumberland river near Nashville, W. Cooper.
My Cabinet.
Cabinet of W. Cooper.

AND DESCRIPTIONS OF NEW SPECIES. 105

Cabinet of the Lyceum of Natural History of New York.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. five-twentieths, Length four-twentieths of an inch.

- Remarks.—This very curious and interesting species was among the
fresh water shells so disinterestedly sent to me by the Lyceum of Na-
tural History of New York to be examined and inserted in this paper.
It has the singular property of strengthening its whirls by the agglu-
tination of particles of sand, &c. by which it is entirely covered, and in
this character it resembles the Zrochus agglutinans, Lam. (Trochus
conchyliophorus, Authors.) 'The apex in all the specimens which I
have had an opportunity of examining is broken. The operculum was
observed in two specimens sufficiently perfect to exhibit a striated
horny structure.

SUPPLEMENT.
Read before the American Philosophical Society, May 20th, 1831.

SINCE my Memoir, read before the Society last May, went to press,
I have procured several species which I believe to be undescribed ; and
which I now propose to add as a supplement, with some preliminary
observations.

Having had an opportunity to examine many fine specimens
within a few months, particularly those brought to this city by James
Ronaldson, Esq. to whose kindness I am indebted for some very rare
species, I have had an opportunity of observing some cclouring of the
nacre which is exceedingly beautiful and rare. It is a singular fact,
that several species, which may be considered, emphatically, as white in
the nacre, vary slightly by being possessed, very rarely, of a tint of pink
in the lateral and sometimes in the cardinal tooth or in the centre of

Vor. IV.—2 B

106 OBSERVATIONS ON NATADES,

the valve. In the cabinets of W. Cooper, Esq. and Mr R., as well as
my own, are specimens of U. cylindricus whose pearly teeth are beau-
tifully tinged with the most delicate and beautiful pmk. The same
cabinets possess also the U. securis with the lateral tooth tinted in the
same manner. The U. metanever has sometimes, though very rarely,
a tint of pink, and still more rarely of nankeen yellow in the centre
of the beaks. The U. circulus, as observed in a previous memoir, is
sometimes, though rarely, possessed of a pink tint.

Whether all the species with white nacre may sometimes be poss-
essed of this beautiful.variety remains to be observed. ‘These rare
and beautiful variations will undoubtedly, when our cabinets shall be
possessed of all the rare species, constitute the jewels of our collections
and be exceedingly sought after.

The size to which some of the species of the Maiades grow is ex-
ceedingly great. I have in my cabinet the following species, of the
weight and size annexed:

Inches. Inches. lb. oz.
U. plicatus, length 4:6, breadth 6:8, weight 1 10.
U. multiplicatus 4:9, 6-2, a
Symphynota alata* 4:2, eA, 0 11.
Symphynota complanataf 5:1, 7-2, 0.15.

Nearly all the specimens which I have seen of the U. soleniformis
(nobis) were sent from Louisville. It struck me as somewhat singu-
lar, that a species so fragile should exist about the falls of a large river,
the force of whose waters there is well known. In explanation of
this, I have been informed by Mr T. W. Taylor of that city, that they
are found to congregate under large flatstones. Unacquainted with this
fact he searched in vain for a long time without finding a single alive
specimen, while odd valyes were not uncommon. They were first
discovered in this situation by raising a stone to take a common craw-
fish, which had taken refuge there. ‘This character seems to be pecu-
liar to this species. ;

My sister, Mrs Febiger of Cincinnati, mentioned to me a_pe-

* Unio alatus, Say. } Alasmodonta complanata, Barnes.

AND DESCRIPTIONS OF NEW SPECIES. 107

culiarity in the habits of the Unio oriens. This shell is possessed
of so small a portion of nacre, that in some specimens the epidermis
may be said to be as thick as the nacre itself. It is obvious
therefore that the rolling of stones and sand carried by the rapidity of
the current of the Ohio upon them, would destroy them if they took
the same position with other species embedded merely in the surface
of the sand. This they avoid, and, burying themselves from six to
twelve inches in the sand, can only be discovered by a small round hole
at the surface through which they receive their supply of water.

In the description of U. varicosus*, I ought to have mentioned
that I did not hesitate to make use of that name, although already used
* by Lamarck, having no doubt but that his species was the lasmo-
donta undulata} (Say).

When making some observations on the family Waiades, Vol. III. p.
442, I mentioned in a note upon the genus Castalia, that it must be
considered as a species of the genus Unio. Having recently procured
from Paris a perfect specimen of it, I have given it a close examina-
tion, and do not now feel by any means certain that it ought not, in
the present received division of the family, to be considered a distinct
genus. ‘The crenulations of the cardinal and lateral teeth in this speci-
men are very distinct, which was not the case in the single valve which
I formerly examined. In this character it has a slight approach to
the family rcacea ; and Lamarck very justly says, “comme elle semble
fluviatilet, elle owe que les trigonées iemeat une transition des
arcacées aux nayades.”

Lamarck, in his description of the Castalia, makes no mention of the
position or existence of the muscular impressions of this genus. In
examining this character, I have discovered that the same observa-
tions made at page 67, in relation to the cicatrix of the extensor mus-
cles of the Hyria avicularis, wiil equally well apply to the genus Cas-
talia, and it is very remarkable that it should be so differently situated
from the same cicatrix in the genus Unio.

* See Vol. IV. p. 90. + See Vol. III. page 424,
¢ There cannot be a doubt of its being fluviatile.

108 OBSERVATIONS ON NAIADES,

In ascribing the locality of York river, Virginia, to the U. obesus,
I have reason to believe there is an error. It was so labelled in the
collection of the Lyceum of Natural History of New York; but this,
Major Le Conte assures me, must have been done by some transfer or
accidental change of the labels; as he procured them in Georgia,
from whence he recently obtained a new supply of undoubtedly the
same species, and those marked as from York river cannot be traced to
that locality. The locality was a matter of surprize to me when I re-
ceived them as coming from that river.

Unto Onrvarius. Plate XVI. fig. 38.

Testa ovatd, transversa, inflata, pellucida; valvulis pertenuibus; natibus promi-
nulis; epidermide pertenui, levi et olive colorem habente; dentibus cardinalibus
magnis laminatis erectisque, lateralibus laminatis brevibusque; margarita pertenut
albaque.

Shell ovate, transverse, inflated, pellucid; valves very thin; beaks slightly elevated;
epidermis olive, very thin and smooth. Cardinal teeth large, erect and lamelli-
form; lateral teeth short and lamelliform; nacre very thin, white and pearly.

Hab. Burrill river, India, Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences.
Cabinet of Dr Morton.
Diam. °7, Length 8, Breadth 1-5 inches.
Shell ovate, transverse, inequilateral, inflated, pellucid: substance of
the shell very thin; beaks slightly elevated, rounded and devoid of un-
dulations: ligament very small: epidermis olive, very thin and smooth :
rays obscure, cardinal teeth large, erect and lamelliform ; lateral teeth
short and lamelliform: anterior cicatrices slightly confluent : posterior
cicatrices confluent: dorsal cicatrices not perceptible; cavity of the
beaks wide; nacre very thin and bluish white.

PL.XVI Vol. 4.

Urio pyramidatus Uno trigonus .

Unto Olivarinus Unio formosus.

Draw by J.Drayton .

AND DESCRIPTIONS OF NEW SPECIES. 109

Remarks.—This interesting little shell is from the fine collection
made by Dr Burrough during his travels in India, and I am indebted
to his kindness for the specimen figured. It is a perfectly distinct
species, and may easily be recognised by its form,its pellucidness, and
its smooth olive-coloured epidermis. It somewhat resembles a young
Anodonta on the exterior, but the elevated lamelliform teeth easily
distinguish it from Mae genus. Its resemblance to a Spanish olive
is very striking.

Unto Pyramipatus. Plate XVI. fig. 39.

Testa sub-pyramidata, longitudinali, inflaté; valvulis antice crasstoribus; nati-
bus maxime prominentibus, recurvis; dentibus cardinalibus magnis crenatisque;
lateralibus longis, a cardinalibus separatis, ad baseos marginem vergentibusque;
margarita colorem carnis habente.

Shell sub-pyramidal, longitudinal, inflated; valves thick anteriorly, thinner pos-
teriorly; beaks very much elevated, recurved; cardinal teeth large and crenate ;
lateral teeth long, distinct from the cardinal teeth and pointing towards basal mar-
gin ; nacre flesh colour.

Hab. Ohio, T. G. Lea.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of P. H. Nicklin.
Unio undatus? Barnes, Var. a.

Diam. 1-7, Length 2:3, Breadth 2-4 fualies,

Shell sub-pyramidal, longitudinal, inequilateral, anterior part swol-
len. recurvely from the beaks to the basal margin, compressed at pos-
terior margin, slightly depressed anterior to umbonial slope ; substance
of the shell very thick in the region of the teeth and beaks, thin at
posterior margin; beaks very much elevated, recurved and incurved ;
epidermis very dark brown and finely wrinkled; cardinal teeth large,
crenate and deeply impressed in the left valve, single and emerging
from a pit in the right; lateral teeth long, slightly curved, distinct

Vor. IV.—2 C

110 OBSERVATIONS ON NAIADES,

from the cardinal teeth and pointing towards the basal margin; ante-
rior cicatrices distinct, the great one forming a deep pit; posterior
cicatrices distinct, the smaller one being placed at the end of the late-
ral tooth; dorsal cicatrices situated on the under part of the cardinal
tooth; cavity of the beaks deep and angulated: nacre beautifully flesh
coloured, very rarely white.

Remarks.—This very beautiful and interesting shell has heretofore
been considered as the U. mytiloides (Rafin.). It does not however
answer either to the description or figure of that author. It may be
easily distinguished from any described species of this genus by its ex-
ceedingly elevated beaks, and beautiful nacre. In young individuals.
indistinct rays may be observed on the beaks.

Unio Triconvus. Plate XVI. fig. 40.

Testa subtriangulari, inflata, preclivo umboniali (quod carinatum est), depressa;
valvulis crassis, natibus prominentibus, incurvis; dentibus cardinalibus magnis,
lateralibus magnis et subcurvis; margarita alba et iridescente.

Shell subtriangular, inflated, depressed before the umbonial slope which 1s cari-
nate ; valves thick ; beaks prominent, incurved ; cardinal teeth large; lateral teeth
large and slightly curved ; nacre pearly white and iridescent.

Hab. ; Ohio river at Cincinnati, T. G. Lea.
Ohio river at Louisville, T. H. Taylor.
; My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of J. Ronaldson.
Cabinet of the Academy of Natural Sciences.

Diam. 1:5, Length 2, Breadth 2-3 inches.
Shell subtriangular, inflated, nearly equilateral, depressed before the
umbonial slope, angular behind ; umbonial slope carinate; basal mar-
gin emarginate; substance of the shell thick, beaks prominent, in-

AND DESCRIPTIONS OF NEW SPECIES. 1il

curved, and slightly undulated at the tips; ligament short and thick ;
-epidermis brown ; rays obsolete; cardinal tooth large, elevated and
widely cleft in the left valve and emerging from a pit in the right
valve; lateral teeth thick and curved in a direction over the cardinal
tooth ; anterior and posterior cicatrices both distinct; dorsal cicatrices
situated on the under part of the cardinal tooth; cavity of the beaks
deep and angular; nacre pearly white and iridescent.

Remarks. ‘This is rather a rare shell, and being of a group of the
species which are known under the general name of Mytiloides
(Rafin.), it has been considered merely a variety of that species.
Having recently examined this group with very close attention and
with the advantage of very many specimens, I am induced to believe
that it may with great propriety be divided into four species, viz. my-
tiloides (Rafin.), undatus (Barnes), pyramidatus (Nobis), and trigonus.

Unio Formosvus. Plate XVI. fig. 41.

Testa triangulari, ventricosd, transversd; clivo posteriori subplano; radiis irre-
gularibus, interruptis, subacutis; dentibus cardinalibus magnis, lateralibus brevi-
bus subrectisque; margarita alba.

Shell triangular, ventricose, transverse, nearly flat on the posterior slope; rays
irregular, interrupted, and somewhat pointed ; cardinal teeth large; lateral teeth
short and nearly straight; nacre pearly white.

Hab. Ohio river, T. G. Lea.
My Cabinet.

Cabinet of Professor Vanuxem.

Cabinet of P. H. Nicklin.
Cabinet of the American Philosophical Society.
Cabinet of the Academy of Natural Sciences.
Cabinet of Peale’s Museum.
Diam. 1, Length 1-1, Breadth 1-6 inches.

112 OBSERVATIONS ON NAIADES,

Sheil triangular, ventricose, transverse, inequilateral ; posterior slope
wide, nearly forming a plane, and possessing numerous indistinct
ribs; substance of the shell somewhat thick; beaks somewhat promi-
nent and flattened; ligament short; epidermis yellowish, smooth and
shining; rays numerous, irregular, interrupted and pointed somewhat
like an arrow head, on the posterior slope they are very minute ; um-
bonial slope carinate ; cardinal teeth large and double in both valves ;
lateral teeth short, nearly straight and enlarged at posterior end ; an-
terior cicatrices distinct ; posterior cicatrices confluent; dorsal cicatri-
ces situated on the under part of the cardinal tooth; Ray of the
beaks deep and rounded; nacre pearly white.

Remarks.—This beautiful shell has heretofore been considered as a
variety of U. triangularis (Barnes). It has, however, I think, char-
acters sufficiently distinctive to entitle it to rank among the species.
It differs from that species essentially in being less flat on the poste-
rior slope, in the umbonial slope being carinate and not rounded,
in being less transverse and in possessing a sharper edge along the
basal margin. In the friangularis the greatest transverse diameter is
nearer the basal margin than in this species. It is sometimes found
much larger than the specimen here represented, which is selected on
account of its perfection. My largest specimen would weigh | at least
four times as much as this one.

Unio Perritexus. Plate XVII. fig. 42.

Testa ovata, obliqua, nodulorum seriem irregularem (fere mediis in valvulis) a
natibus ad marginem baseos currentem habente; valvulis crassis; clivo umboniali
irregulariter rugato; radiis exiguis et numerosis; dentibus cardinalibus modicis,
lateralibus longis subrectisque; margarita lacteo-albd.

Shell ovate, oblique, having an irregular bauteis line near the middle from the
beaks to the basal margin; valves thick ; umbonial slope irregularly wrinkled ; rays
small and numerous; cardinal teeth rather small; lateral teeth long and nearly
straight; nacre milk white.

PL.XVIE Val. 4.

43

Unio an qustatus

Unio perplexus, Unto arceformiys

Prayvn hu J Drayton

AND DESCRIPTIONS OF NEW SPECIES. 113

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of Professor Vanuxem:
Cabinet of P. H. Nicklin. ©
Cabinet of the Academy of Natural Sciences.
Cabinet of the American Philosophical Society.
Diam. 1°5, Length 1:9, Breadth 2-6 inches.

Shell ovate, oblique, inequilateral, having an irregular nodulous line
near the middle passing obliquely from the beaks to the basal margin;
substance of the shell thick ; umbonial slope irregularly wrinkled ; an-
terior to the umbonial slope is a wide slightly impressed furrow;
beaks prominent, rounded, and situated near the anterior margin; liga-
ment slender and somewhat long ; epidermis smooth, shining, yellow-
ish, with numerous small green rays which thickly cover the whole
disk except a small portion of the anterior part; cardinal teeth rather
small, deeply cleft in the left valve, single and emerging from a pit in
the right valve; lateral teeth long, nearly straight, and slightly en-
larged near the posterior end; anterior cicatrices distinct; posterior
eicatrices confluent; dorsal cicatrices situated on the under part of the
cardinal tooth; cavity of the beaks wide and rounded; nacre milk
white, rarely rose coloured.

Remarks.—This extraordinary and highly interesting shell formed
one of the three divisions into which I had, in my cabinet, separated
the U. cornutus (Barnes). The other division has been called by
Dr Hildreth foliatus. Having, since the publication of my last
memoir*, received numerous young and perfect specimens, I have
concluded that the study of this group would be facilitated by its sepa-
ration into three species, which will stand thus; U. cornutus (Barnes),
possessing three or four distinct horns between the beaks and basal
margin; U. foliatus (Hildreth), having no elevation, but possessed of
two elongations, one at the basal margin, the other at posterior margin ;
and U. perplexus (Nob.), possessed of an irregular oblique nodulous ridge

* See note, Vol. If. p. 418.

Vout. IV.—2 D

114 OBSERVATIONS ON NAIADES,

passing from the beaks to basal margin. The figure represents a per-
fect and beautiful specimen. It sometimes occurs, however, with an
extended posterior portion so large as to be nearly as wide again as the
natural width of the’shell. The pallial impression, nevertheless, does
not advance beyond its natural position, and the space beyond is covered
by a prolonged and hard portion of the fringe of the mantle. The
irregularity of the nodules is very remarkable and varies from one on
each valve to twelve. Where there are few, they are generally much
elevated, and there being a correspondent. depression in the other valve
the specimen’presents a remarkable, and distorted appearance. Speci-
mens are occasionally found of a beautiful rose colour. These, however.
are very rare. ;

;

Unio Ancustatus. Plate XVII. fig. 43.

Testa transversa, sub-compressd, angusto-ellipticd; .valvulis tenuibus; natibus
' prominulis et apicibus undulatis; radiis obsoletis; dentibus cardinalibus elevatis et
compressis, lateralibus longis, subrectisque ; margaritd purpurea et iridescente.

Shell transverse, somewhat compressed, narrow-elliptical, valves thin; beaks
slightly elevated and undulated at the tips; very obsolete; cardinal teeth elevated

and compressed ; lateral teeth long and nearly straight; nacre purple and iri-
descent.

Hab. ; Congaree river, South Carolina.
Cooper river, South Carolina, Professor Ravenel.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of Professor Ravenel.
Cabinet of Major Le Conte.
Cabinet of the Academy of Natural Sciences.
Diam. 7, Length 1:1, Breadth 2:8 inches.
Shell very transverse, somewhat compressed, very narrow-elliptical,
inequilateral ; substance of the shell thin; beaks slightly elevated and

AND DESCRIPTIONS OF NEW SPECIES. 115

undulated at the tips; ligament long and slender; epidermis reddish
brown, rays obsolete; cardinal teeth elevated, compressed and crenu-
late ; lateral teeth long, nearly straight and enlarged at the posterior
end ; anterior cicatrices distinct; posterior cicatrices confluent; dorsal
cicatrices situated in the angle of the cavity of the beaks; cavity of the
beaks wide and shallow; nacre dull purple.

Remarks.—This species resembles somewhat the Unio complana-

tus (Soland.). It will, however, at once be distinguished by its great
proportionate breadth. In this it resembles the U. nasutus (Say), but
may be readily separated from that species by its want of the peculiar
rays of the nasutus and the absence of its postericr enlargement. In the
summer of 1827, I found several young and striking specimens of this
species in the Congaree at Columbia, 8. C. and I am recently in-
debted to Professor Ravenel for several adult specimens, one of which
is represented in the plate. In some specimens the umbonial slope is
more elevated and the basal margin straight.
_ Thave a single specimen nearly white in the nacre; and they will,
most probably, be found of a salmon colour, as well also of all the tints
between these colours, similar to the U. complanatus with which and
some other it seems to form a natural group*.

* Extract from a letter recently received from Professor Ravenel. ‘I have been fortunate
enough to obtain very good series of the two shells which I was anxious to submit to your
examination, as well as a complete series of the complanatus in all the varieties in which it
occurs in Cooper river and its tributary streams. ‘This will enable you to compare the length-
ened shell [the above described species] which I thought distinct, with such specimens of the
complanatus as approach it, and to determine the point. Our shell resembles:the nasutus
closely, particularly the young shell, but is certainly distinct from it. I have never seen the
nasutus in this state or in North Carolina.”

Charleston, South Carolina, May 27th, 1831.

116 OBSERVATIONS ON NAIADES,

Unio Arczrormis. Plate XVII. fig. 44.

Testa arceformi, valde ventricosa, transversa; clivo posteriori latissimo et sul-
cum curvum habente; valvulis precrassis; radiis capillaribus; dentibus cardinalibus
crassis, lateralibus brevibus rectisque; margarita alba.

Shell arceeform, very ventricose, transverse ; posterior slope very wide and poss-
essed of a curved furrow ; valves very thick; rays hair-like ; cardinal teeth thick ;
lateral teeth short and straight ; nacre white.

Hab. Tennessee river, Professor Vanuxem.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of W. Cooper.

Diam. 2, Length 2, Breadth 2-5 inches.

Shell subtriangular, very ventricose, transverse, inequilateral; pos-
terior slope very wide, and nearly flat except at the termination of the
ligament, possessed of a curved furrow enlarging from the beaks to the
posterior margin; substance of the shell very thick; beaks prominent
and incurved ; ligament short and thick; epidermis yellowish brown ;
rays hair-like and numerous ; cardinal teeth thick and irregular ; late-
* ral teeth short, straight and crenate ; posterior cicatrices confluent ; an-
terior cicatrices distinct; dorsal cicatrices situated on the under part of
the cardinal tooth; cavity of the beaks shallow and rounded ; nacre
white.

Remarks.—I have been in possession of a single specimen of this -
species for some years. It was brought by Professor Vanuxem from
the Tennessee river, and, being old, some of its characters have nearly
disappeared. I frequently examined it with great interest, and felt
persuaded it was a new species, although it strongly resembled the fi-
angularis (Barnes).. A young and an adult specimen, recently sent
me from New York by that excellent naturalist W. Cooper, proves it
beyond a doubt to be a distinct species. In its rays it differs altogether
from the triangularis; it is dissimilar also in the thickness of the valves and

ras orm maga
We eis *
COG Ti rwnccaeionnert

Trio subovatus .

Unro subrotundaus -

Gaia pileus.

Drawn bry Dra yton

ry

AND DESCRIPTIONS OF NEW SPECIES. 117

in the possession of two remarkable curved furrows on the umbonial

slope. The specimen represented in the engraving is chosen on ac-

count of its being adult, although the beaks are notin a perfect state of

preservation. The enlargement and dentate appearance of the poste-

rior margin is very remarkable in this and some other of the species.

It occurs more frequently in the sw/catus (Nobis), and has been par-

ticularly noticed in the remarks on that species*. ‘This variety of .
sulcatus has been considered by Mr Say as a distinct species, to which

he has given the name of ridibundus. I have never thought that it

could be considered to differ specifically from the sulcatus.

Unio Susrotunpus. Plate XVIII. fig. 45.

Testé suborbiculatd, subventricosd; valvulis crassis; natibus prominentibus; epi-
dermide circa nates luted, juxta marginem fuscd; radiis interruptis; dentibus car-
dinalibus crassis, lateralibus subcurvis brevibusque; margarita alba et iridescente.

Shell suborbicular, subventricose ; valves thick ; beaks elevated; epidermis yel-
low about the beaks, brown towards the margin ; rays interrupted; cardinal teeth
thick ; lateral teeth short and slightly curved ; nacre pearly white and iridescent.

Hab. Ohio, T. G. Lea.
My Cabinet. .

Diam. 1-1, .-. = Length 16,0 Breadth 1-6 inches.

Shell suborbicular, nearly equilateral, subventricose; substance of
the shell thick, somewhat thinner behind; beaks thick and elevated ;
ligament rather short and thick; epidermis yellow and smooth in the
region of the beaks; brown and finely wrinkled towards the margin;
interrupted rays pass from the beaks and are very visible over the um-
bones, but are lost in the wrinkles before they reach the margin; car-
dinal teeth thick and crenate; lateral teeth short, thick and very
slightly curved; posterior and anterior cicatrices both distinct; dorsal

* See Vol. HII. p. 431.
Vou. IV.—2 E

118 ' OBSERVATIONS ON NAIADES,

cicatrices situated on the under side of the cardinal teeth; cavity
of the beaks deep and angulated: nacre pearly white and iridescent.

Remarks.—Among the numerous shells I have received within the
last five years from our western waters, I have obtained but three or
four of this interesting species. Its extreme rarity at first induced me
to doubt of the propriety of considering it a distinct species. It is
however, perfectly distinct from any described species and seems pe-
culiar in its yellow beaks and brown margin; as well as in the beauti-
ful interrupted rays which pass over the umbones, leaving the ante-
rior and posterior slopes usually of a yellow colour. In form it
approaches the ebenus (Nobis), in colour it more nearly resembles
the undatus (Barnes). A young individual of not more than three
growths presents such a shining and yellow epidermis as to resemble
very much a small Venus.

Unto Susovatus. Plate XVIII. fig. 46.

' Testa subovata, transversa, inflata ; valvulis crassis ; natibus prominentibus et
apicibus undulatis ; multis radiis viridibus; dentibus cardinalibus erectis et in
valvuld utraque duplicibus, lateralibus laminatis brevibusque; margarita alba.

. Shell subovate, transverse, inflated ; valves thick ; beaks elevated and undulated
at the tip; rays green and numerous; cardinal teeth double in both valves and erect;
lateral teeth short and lamelliform; nacre white and very pearly.

Hab. Ohio river, T. G. Lea.
My Cabinet.
Cabinet of John Ronaldson.
Cabinet of the Academy of Natural Sciences.
Diam. 2:2, Length 3, Breadth 4-2 inches.
Shell subovate, transverse, inequilateral, inflated; substance of the
shell thick ; beaks elevated, incurved and undulated at the tips; liga-
ment short and thick; epidermis yellowish with numerous green rays

AND DESCRIPTIONS OF NEW SPECIES. 119

passing obliquely from the beaks to the margin; cardinal teeth large,
double in both valves, very erectand deeply cleft in both valves ; lateral
teeth short and lamelliform ; anterior cicatrices distinct ; posterior cica-
trices confluent ; dorsal cicatrices situated within the cavity of the shell
on the under part of the cardinal tooth and on the plate between the
cardinal and lateral teeth ; cavity of the beaks very large and rounded ;
nacre white and very pearly.

Remarks.—This species is very closely allied to the U. ovatus (Say)
and U. occidens (Nobis). It differs constantly, however, from both, in
being more produced posteriorly, and in the position of the beaks
which are placed nearer the anterior margin. It is less flattened on
the posterior slope than the ovatus, and less carinate than the oceidens.
Like both these species the anterior section of the cardinal teeth is the
most elevated. In some specimens no rays are observable*,

Unto Prrevs. Plate XVIII. fig. 47.

Testi. sublriangulari, ventricosa, preclivo umboniali in longum subsulcata,
emarginata; valvulis crassis; radiis capillaribus; dentibus cardinalibus magnis,
lateralibus breviusculis subcurvisque; margarita alba et iridescente.

Shell subtriangular, ventricose, slightly emarginate, longitudinally furrowed in

* Since this supplement went io press I have seen in the fine collection of that excellent
conchologist, Mr W. Hyde, a specimen sent him by Mr Barnes some years since as U. ven-
tricosus. If this specimen be not of the same species as the above described, it certainly very
closely resembles it. Never having seen the individual specimen described by Mr Barnes as
ventricosus, I believed, from that part of the description in which he says ‘ this shell is more
capacious than any other of the genus hitherto described,” that he meant the species known to
us as globosus, and therefore I selected of the two species that which seemed to agree the least
with his description, and figured and described it. Should it, upon further examination, prove
that I have described the same shell with Mr Barnes, the name of globosus should be used to
distinguish this capacious species, specimens of which are in the cabinets of Mr Hyde, the
Academy of Natural Sciences, Peale’s Museum, and in my own. Mr Barnes must, I think, be
in error in supposing the ventricosus to inhabit the Delaware, or New Jersey near New York,
1 do not think that any of the group belong to our eastern waters.

120 OBSERVATIONS ON NAIADES,

front of the umbonial slope; valves thick; rays hair-like; cardinal teeth large; lateral
teeth rather short and slightly curved; nacre pearly white and iridescent.

Hab. Ohio river, near Cincinnati, Mrs Febiger.
My Cabinet.

Diam. 1-2, Length 1:8, Breadth 1-8 inches.

Shell subtriangular, angular behind and rounded before, ventricose :
longitudinally furrowed in front of the umbonial slope, the furrow
causing a slight emargination in the basal margin; umbonial slope flat-
tened on the ridge ; substance of the shell thick; beaks prominent and
rounded at the tip; ligament short and thick; epidermis yellowish-
brown and wrinkled ; rays numerous and hair-like ; cardinal tooth large,
elevated and deeply cleft in the left valve, single and emerging froma
pit in the right valve; lateral teeth short and slightly curved; anterior
cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices
situated on the under part of the cardinal tooth; cavity of the beaks
wide and rounded; nacre pearly white and iridescent.

Remarks.—This shell has recently come into my possession and was
taken near Cincinnati. It is different from any species I have seen,
and somewhat resembles the U. sulcatus (Nobis), having a furrow from.
the beaks to the margin anterior to the umbonial slope. It differs
from it, however, in being more elongated and in being destitute of a
purple nacre. The disposition to flatness in the umbonial slope is re-
markable in this species.

-Metanra Evoneata. Plate XV. fig. 29.

Testa elevata et acute turrita, fusco-corned, purpureo-fasciata; anfractibus circi-
ter decem parum depressis; basi angulata; apertura ceruleo-alba, longitudinis testa
quadrantem habente.

Shell elevated and acutely turrited, dark horn colour with purple bands; apex
acute; whirls about ten and slightly depressed; base angulated; aperture bluish-
white and about one fourth the length of the shell.

AND DESCRIPTIONS OF NEW SPECIES. 121

Hab. West Tennessee, John Lea.
My Cabinet.
Diam. -5, Length 1-5 inches.

Remarks.—This fine Melania seems most to resemble the subu/aris
(Nobis). It differs from it in being wider, in being darker coloured,
andin having a less number of whirls. The bands in some specimens
are scarcely visible. |

I cannot terminate this memoir without making my grateful ac-
knowledgements to numerous friends for specimens sent from time to
time for my examination or acceptance. To P. H. Nicklin, Esq.
and to W. Cooper, Esq. Iam under particular obligations, for their
kind and prompt assistance on such difficult points as appeared to me
to require consultation.

Vou. IV.—2 F

ARTICLE VI.

Description of a new genus of the family Melamana of Lamarck.
. By Isaac Lea. Read January 7th, 1831.

Famiry MELANIANA.
Genus [o.

Testa fusiformt ; basi canaliculaté ; spiré elevatd; columellé concavé levique.

Shell fusiform ; base canaliculate; spire elevated; columella smooth and concave.

Io Fusitrormis. Plate XV. fig. 37, a, b.

My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of Mr Say.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Fusus fluvialis, Say, Journal of the Academy of Natural Sciences
of Philadelphia, Vol. 5, p. 129.

Diam. -9, Length 2-2 inches.
Remarks.—This very remarkable, interesting and rare shell was
presented tome many years since by Professor Vanuxem, by whom only
it has been found. Specimens were also presented by him to Mr Say

NEW GENUS OF THE FAMILY MELANIANA. 123

and to the Academy of Natural Sciences of Philadelphia, in the Jour-
nal of which that naturalist has described it under the name of Fusus
fluvialis. Satisfied that no genus should contain pelagian and fluvia-
tile shells in common, I have separated this from the family Canaui-
FERA, and placed it in that of the Menanrana to which it naturally
belongs. We are indebted to the research of Professor Vanuxem for
this and many other fine shells from the north fork of the Holston in
Virginia on the farm of General Preston, where it was associated with
several species of this and other families. Professor Vanuxem de-
scribes the spot which it inhabits as being very circumscribed and be-
ing immediately at the confluence of a small stream and the North
Fork of the Holston, the former of which is slightly impregnated
with salt.

a
’ he

he
Sean
yee i

Paes Nit

23

ARTICLE II.

Observations on the Naiades ; and Descriptions of New Species of thai.
and other Families. By Isaac Lea. Read before the American
Philosophical Society March 16, 1832.

PRELIMINARY REMARKS.

In presenting myself again before the Society with a new memoir in
that department of conchology which has so much engaged my atten-
tion for some years, an apology would seem almost necessary. My
zeal and love for the science generally will, I trust, be sufficient for
my present intrusion on its time.

The family aiades seems to have excited very little interest with
the older writers on natural history, and not much more among mo-
dern zoologists until within the present century.

The progress of general knowledge, and the improvements in the
mechanic arts, have recently been greatly accelerated, and the disco-
veries and improvements in the study of natural science, have gone on
“pari passu” with them; and we have every reason to believe that the
momentum which they have acquired will not be diminished, for, to
use the words of one of the most successful writers of the present day.
“there is growing up an enlightened public opinion” which no power
is likely to arrest, and which must carry us far towards a perfect state

24 ON THE NAIADES,

of knowledge, while there is such a “ diffusion of existing knowledge
among the mass of mankind” as we have at present.

We can only account for the almost total neglect of the family
Naiades by writers on natural history of the last century, in the fact
that the fresh waters of Europe produce so few species that they had
then scarcely attracted attention. The habits of these animals have
been there so little studied and known, that some recent writers of
reputation assert that they move with the beaks of the shell “ down-
ward,” which is equivalent to saying they walk on their backs. The
anterior part has been called the posterior part, which is as much as
to say, that their locomotion is backward.

These facts display a great want of attention to the animal in its
element,—where it would be observed to possess many curious and
striking characteristics. ‘The great systematist, the immortal Linneus,
whose name will be found recorded in the book of the last student of
natural history, knew so few members of this family that he classed
them indiscriminately with two marine genera, Mya and Mytilus.

It was the rich and splendid productions of the rivers of the United
States, and particularly those which are tributary to the Mississippi,
which first roused the attention of the zoologist to their extraordinary
characters; and they have within a few years become sought after by
collectors as eagerly as the “ most precious jewels of the ocean.”

Urged by the solicitations of numerous scientific friends, I have
continued my efforts to obtain such specimens as appeared to me to be
new and undescribed, and they are now submitted to the consideration
of the Society.

In my communications I have heretofore said little on the geogra-
phical position of our Naiades. It has, however, been to me an inte-
resting branch of the subject, and engaged much of my attention.
The great dividing ridge or chain of mountains, the Alleghanies, which
seems so completely to separate our eastern from our western waters,
almost as completely separates the species of this family inhabiting
those parts lying east and west of it. It is a matter of doubt if there
be more than two or three species of all the genera of this family ex-
isting in the eastern waters which have their analogues in the western
waters. That shell, which we have considered the Unio cariosus of

AND OTHER FAMILIES. 25

the Ohio, certainly has a different aspect from that of our eastern rivers,
and might with great propriety be referred to the name which Mr Say
gave it long since, viz. U. crassus.* There is another shell, however,
in the Ohio, which has a stronger resemblance than this, and I believe
it to be the analogue of the Alasmodonta marginata (Say). I have
examined numerous specimens of this species frequently and attentively:
but cannot distinguish any difference except in the size, the western
shell being generally much larger. Of the numerous species and
genera of the families Lymneana, Melaniana and Peristomiana, I have
never seen a single species common to both waters. ‘To the genus
Cyclas I have given but little attention, but believe the same observa-
tions may be extended to this species.

What an interesting field do these facts spread open to the inquiring
philosopher! Why should the streams which flow down the sides of
the same range of mountains, east and west, differ so essentially in
their productions?

Let us now examine the extremities of this great chain. To the
north, where it is lost in the high lands which spread out along the
southern boundaries of the small lakes in the state of New York, great
difficulty naturally occurs in defining the line of separation. So far as
my observation has extended, the shells of the river Mohawk and its
tributaries are the same with those of the Delaware, Potomac, &c. with
the exception of a single species Symphynota compressa (nobis), which
is found near Albany, and which exists also in the Ohio. The tribu-
taries of the lakes Erie, Michigan, &c., with few exceptions, produce
the western species, and consequently the lakes do also.t

The great river Niagara, or rather strait connecting the lakes Erie
and Ontario, furnishes us with the U. triangularis (Barnes), and other
species, which are so peculiarly characteristic of our western waters.
Never having visited the shores of lake Ontario, I cannot pronounce on
its productions. The shells of the river St Lawrence are, I believe,

* A shell which I have always considered as a truncated variety of U. crassus of the Ohio,
has by this naturalist been made a new species under the name of U. abruptus.

+ Since writing the above I have received the U. complanatus (Soland.) from Lae Vaseux,
which empties into Green Bay; and more recently the same species from lake Champlain.
The U. nasutus (Say) has been observed in Grand river, which disembogues into lake Erie.

VOL. V.—G

26 ON THE NAIADES,

impressed with the character of those of the lake. In this river there
is, however, little to my knowledge interesting to the conchologist.

Lake Champlain, which empties its waters into the St Lawrence,
is prolific in some of the western species. The Symphynota alata, the
Unio occidens and the Unio rectus, with some other western species,
are found there in great perfection, but none of the tuberculated or
undulated species.

The southern extremity of the Alleghany ridge is supposed to reach
into the upper part of the state of Alabama, where it terminates by
spreading out into high lands east of the river Tennessee, and near to
that part where the river makes its most eastern angle. The sources
of the Alabama and Tombeckbee rivers, which discharge themselves
into the Gulf of Mexico, are situated in these high lands, and the char-
acter of the shells of these rivers is completely the same with those
of the western waters. In no instance have I observed a shell from
these rivers, or the Mississippi, which possessed the characters of those
of our eastern rivers. ‘To draw the exact line of distinction here, in
the present state of our knowledge, is impossible; but that such a line
does exist there can scarcely be a doubt.

The great difficulty experienced by naturalists in procuring speci-
mens from newly settled and distant parts of the United States is such,
as to deprive us of much desirable information. This impediment
will, it is hoped, be overcome in time, and the natural history of our
country become universally known.

In the present state of our knowledge, we can only place this line
somewhere between the Alabama and the Altamaha rivers. From
the latter, I have seen but a single valve, which I owe to the kindness
of Mr Nuttall. This is the U. complanatus (Soland.), and marks dis-
tinctly the character of the shells of this river to appertain to that of
the eastern waters. From the river Appalachicola I have never been
able to procure a single specimen, and it remains yet to be proved
whether it produces shells of the eastern or western character. As,
however, it disembogues in the Gulf of Mexico, it is more than proba-
ble that it possesses the same species as the western waters, and its
neighbour the Alabama.

In regard to the shells of the soil, it will naturally be asked if they

AND OTHER FAMILIES. Q7

also differ so completely as those of the rivers on the two sides of the
great ridge? In these the distinction does not exist, for we find almost
every species which is common on the eastern, equally common on
the western side. There are, however, some species which are not
uncommon on the western side, but which do not exist, so far as my
information extends, on this side. If it be demanded why the line of
demarcation should not be as perfect for terrestrial as fluviatile shells,
we might say in answer, that the barrier of a mountain could in time
be overcome even by the slowly travelling snail. Surely in the lapse
of time the progeny of those which accidentally began to climb the
steeps, might descend into the valleys of the opposite side.

In finishing these introductory remarks, [ wish to call the attention
of those naturalists who are conveniently located, to make further ob-
servations on this branch of the science, which certainly has great in-
terest.

In describing the Valvata arenifera in my last memoir, Vol. IV.
page 104, I was impressed with the idea, from the circumstance of
finding a true operculum combined with a spiral tube, that the animal
must have belonged to the family Peristomiana. I have reason, how-
ever, since, to doubt the truth of my conclusions. Professor Troost,
now at Nashville, Tennessee, originally sent the specimens from that
neighbourhood ; and from his description of the animal, which he has
recently communicated to me, I am induced to believe it to be a spe-
cies of Linnean Phrygania.

28 ON THE NAIADES,

Unto Nicxurnianus. Plate I. fig. 1.

Testa subtrigond, inequilaterali, obliqud, maxime undulatd, usque ad natium
apices ; valvulis crassissimis ; dentibus lateralibus crassis curvisque ; cardinalibus
maxime crassis; margarité alba et iridescente.

Shell subtriangular, inequilateral, oblique, very much undulated, even to the point
of the beak; valves very thick; cardinal teeth very thick; lateral teeth thick and
curved ; nacre pearly white and iridescent.

Hab. China.
My Cabinet.

Diam. 2, Length 5, Breadth 5:S inches.

Shell subtriangular, oblique, very much spread out, with an elevated
wing, flattened towards the beaks, the greatest diameter being near the
posterior basal margin, covered with numerous undulations, except on
the anterior and basal margins; undulations diverge from the beak, and
are largest near the posterior margin: substance of the shell very thick
in the region of the basal margin; beaks pointed but not elevated, cov-
ered with numerous beautiful literations to the very point; epidermis
dark brown; cardinal teeth very large, thick and sulcate ; lateral teeth
thick and curved ; anterior cicatrices rough and distinct ; posterior cica-
trices slight and confluent; dorsal cicatrices situated on the under side
of the cardinal tooth; cavity of the beaks angular; nacre pearly white,
very iridescent on the posterior part, where the undulations are visible
from without.

Remarks.—I met with this very interesting species in the autumn of
1831 at a dealer’s in New York. I was informed that it was supposed
to be from China. A single valve only could be obtained, and this
unfortunately not entirely perfect. The characters are, however, so
distinct from any species I have seen, that i have not hesitated to give
it a place among my new species. It is remarkable for its great extent
from the top of the wing to the basal margin, and for its numerous
undulations. In outline and diameter it resembles the Symphynota
complanata (nobis) (Alasmodonta complanata of Barnes), but differs in
being less transverse, higher in the wing, and more thickly covered

Drawn by

Unio Nicklintanws

PL. IW Vol. 5

Unio sudglobosus,

Unio capillaris . 4 1
Unto capsaformis,

Drawn by J.Drayten.

AND OTHER FAMILIES. Q9

with undulations. In the possession of many folds, it resembles the
UT. multiplicatus (nobis), but differs in outline (being much less trans-
verse), as well as in the size of the undulations, which are much smaller.
The point of its greatest diameter is much nearer the posterior basal
margin than in the multiplicatus. The imperfect state of this speci-
men has prevented me from describing the ligament. Judging from
its elevated wing, Iam much inclined to believe that when perfect
specimens are procured they will be found to be connate. If so, it
will belong to a natural division removed from Unio, viz. Symphynota.
I have dedicated this fine species to my friend P. H. Nicklin, Esq., of
Philadelphia.

Unto capituaris. Plate II. fig. 2.

Testa suborbiculatd, ventricosd, subequilaterali, postice subangulatd ; valvulis
subcrassis; natibus prominentibus; epidermide nitide rugatd; radiis numerosis
capillaribusque ; dentibus cardinalibus valde elevatis ; lateralibus lamellatis et sur-
sum subreclivis ; margarita alba et iridescente.

Shell suborbicular, ventricose, subequilateral, subangular posteriorly; valves rather
thick ; beaks elevated; epidermis finely wrinkled ; rays numerous and capillary ; car-
dinal teeth much elevated ; lateral teeth lamellar, and inclined to curve upwards; nacre
pearly white and iridescent.

Hab. Ohio. 'T. G. Lea.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam 1:2, Length 1-5, Breadth 1-9 inches.

Shell suborbicular, ventricose, subequilateral, subangular posteriorly :
substance of the shell rather thick anteriorly; thinner posteriorly ;
beaks thick and elevated; ligament short and thick; epidermis dark
and finely wrinkled, smoother towards the beaks; rays numerous,
capillary, and spreading over nearly the whole disk; cardinal teeth
elevated, crenate, deeply cleft in the left valve, and rising from a pit
in the right; lateral teeth lamellar, crenate, inclined to turn upwards;
anterior cicatrices distinct; posterior cicatrices confluent; dorsal cica-

VOL. Y.—H

30 ON THE NAIADES,

trices situated on the under side of the cardinal tooth; cavity of the
beaks obtusely angular; nacre pearly white and iridescent.

Remarks.—I have had a single specimen of this shell for some years,
and although satisfied it differed from any described species, I deferred
bringing it forward until I should have an opportunity of examining
more. In the fine collection of the Academy of Natural Sciences
I found a second specimen, which so completely coincided in all its
characters with mine, that I deemed it unnecessary to hesitate erecting
it into a species. Both the specimens have that enlargement of the
inferior portion of the umbonial slope mentioned in the remarks on the
U. Haysianus herein described, which usually causes a remarkable and
curious denticulation of the margin, and a poverty of the deposition of
the nacre in that region. It has, perhaps, a stronger resemblance to
UY. ellipsis (nobis) than to any other species. It is however more
rotund, more minutely rayed, and less oblique.

Unio suscioposvs. Plate II. fig. 3.

Testa subglobosd, subxquilaterali, inflata et postice subangulataé; valvuilis
crassis ; natibus prominulis rotundatisque ; dentibus cardinalibus latis striatis-
que, lateralibus subcurvis ; margaritd subrufd, vel colore caryophylli tinctd.

Shell subglobose, nearly equilateral, inflated, subangular behind; valves thick ;
beaks slightly prominent, rounded; cardinal teeth wide and striated ; lateral teeth
somewhat curved ; nacre pearly and pink coloured.

Hab. Bayou Teche, Louisiana. W. M. Stewart.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Mr Stewart.
Cabinet of William Hyde.
Cabinet of P. H. Nicklin.
Diam. 1-6, Length 2-1, Breadth 2:9 inches.
Shell subglobose, subequilateral, subangular behind, inflated; sub-
stance of the shell thick; umbonial slope carinate; beaks slightly pro-

AND OTHER FAMILIES. 31

minent, rounded; ligament rather short and thick; epidermis dark
brown or black; cardinal teeth wide, striate, but not divided; lateral
teeth somewhat curved, serrate and separated from the cardinal teeth
by the absence of a plate; anterior cicatrices distinct, posterior cica-
trices confluent and large; dorsal cicatrices situated across the cavity
of the beaks and very distinct; cavity of the beaks large and rounded ;
nacre pearly and pink coloured.

Remarks.—This very distinct species is one of the many fine shells
collected by Mr Stewart in the Bayou Teche. It perhaps most re-
sembles an inflated specimen of U. cuneatus (Barnes). It may, how-
ever, at once be distinguished from that species by its peculiarly beau-
tiful pinky lustre and striate cardinal teeth, as well by its globosity.
The strie of the cardinal teeth diverge from a point beneath the
point of the beaks, and in its flatness and absence of a cleft these
teeth resemble those of the U. rubiginosus (nobis).

Unto capsxrormis. Plate II. fig. 4.

Testa ellipticd, transversd, inequilaterali, subinflatd, postice subtriangulaté ;
valvulis antice crassioribus ; natibus prominulis ; dentibus utriusque valvule car-
dinalibus, elevatis duplicibusque ; lateralibus elevatis et lamellatis ; margarita
alba et iridescente.

Shell elliptical, transverse, inequilateral, somewhat inflated, sub-biangulate poste-
riorly ; valves thicker anteriorly ; beaks slightly elevated ; cardinal teeth elevated and
double in both valves ; lateral teeth elevated and lamellar ; nacre pearly white and iri-
descent.

Hab. Cumberland River. W. Cooper.
My Cabinet.
Cabinet of W. Cooper.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. .9, Length 1.3, Breadth 1.9 inches.
Shell elliptical, transverse, inequilateral, somewhat inflated, flattish
before the umbonial slope, sub-biangulate posteriorly; substance of the

32 ON THE NAIADES,

shell thick anteriorly and thin posteriorly; beaks slightly elevated and
rounded; ligament short and thick; epidermis yellow, with numerous
small green rays; cardinal teeth elevated, double and crested in both
valves; lateral teeth elevated and lamellar: anterior cicatrices distinct;
posterior cicatrices confluent; dorsal cicatrices situated within the
cavity of the shell on the plate between the cardinal and lateral teeth
and on the base of the cardinal tooth; cavity of the beaks wide and
obtusely angulate; nacre white on the anterior and iridescent on the
posterior portion.

Remarks.—While engaged in my last memoir, this shell attracted
my attention. I had not, however, then, an opportunity of examining
more than two or three specimens, and finding they differed much in
some characters, I deferred noticing them. I owe to Mr Cooper the
advantage of examining his specimens, which convinced me the species
was distinct. This is one of those species which sometimes dilate or
increase about the region of the umbonial slope, and in this and its
rays it resembles, in a slight degree, the U. perplexus (nobis). The
enlargement of this portion of the shell, which is generally a deep
green, causes it to have a different outline, being there more rounded
and causing the basal margin to be arcuate.

Unro Ravenetrants. Plate III. fig. 5.

Testa late ovata, obliquad, inequilaterali, postice subanguluté ; valvulis antice~
erassioribus ; dentibus cardinalibus crassis brevibusque ; lateralibus crassis rec-
tisque; margarité alba et iridescente.

Shell widely ovate, oblique, inequilateral, subangulate posteriorly; valves thicker
anteriorly ; cardinal teeth short and thick; lateral teeth straight and thick ; nacre pearly
white and iridescent.

Hab. French Broad River, tributary to the Tennessee, near Ashe-
ville. N. C. Professor Ravenel.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Pr. IM Vol-o! .

oat in . : 2
Unie Murchisonianus . Unto Htldrethianus.

?

. L- , ~ me
Mnio Ravanellanits . Unio Haysionus . Unie Schoolcraft
, € ww a POMNILN

ae

Sha:

“it ba HT

~igpt ions rely x a fee a0 aca
Se ee

eehmentie waa: A: omy eI

Bess oo RN Rall, - ike
io iby ipo ene in Artin

aan Boa me ae Si vA mad i .

Pease RR ole e —
ies ee ee te
Brad te Sia 9 a Big r Mid po nd

Des oe ie Cae ean Oe, ewe
bt ; is i

»

bp

AND OTHER FAMILIES. 33

Cabinet of Professor Ravenel, Charleston, 8. C.
Cabinet of P. H. Nicklin.
Cabinet of Professor Vanuxem.

Diam. 7, Length :9, Breadth 1-5 inches.

Shell widely ovate, oblique, inequilateral, subangulate posteriorly,
slightly inflated, compressed at posterior and inferior margins; substance
of the shell thick and white anteriorly, thin and iridescent posteriorly ;
ligament short and thick; epidermis dark brown and finely wrinkled ;
cardinal tooth short, thick and deeply divided in the left valve, single
and rising from a pit in the right valve; lateral teeth oblique, straight
and thick, having a direction over the lateral tooth; anterior and pos-
terior cicatrices both distinct ; dorsal cicatrices situated within the cavity
of the shell on the plate between the cardinal and lateral teeth ; cavity
of the beaks shallow and rounded; nacre white in the anterior, and
iridescent in the posterior portion.

Remarks.—This shell, which I owe to the kindness of Professor
Ravenel, has, I believe, been first noticed by that gentleman, who, sup-
posing it to be new, sent it to me about a year since. It differs in its
outline from any of our eastern species, as it does also in its obliquity.
In these characters it most resembles the U. patulus (nobis) ; it is, how-
ever, more dilated,—in some specimens the margin being subrotund.
The only specimens obtained by Professor Ravenel being imperfect,
and much eroded at the beaks, I have not described that part, leaving
it for future observation. ‘There are no rays to be observed on the
specimens I have. In young or fine specimens, it is very possible they
may exist.

Unto Murcuisonranvs. Plate III. fig. 6.

Testa angulato-ellipticd, transversd, inxquilaterali, valvulis tenuiculis ; natibus
perplicatis ; dentibus cardinalibus in valvuld utrdque duplicibus, lateralibus rectis ;
margarita pulchrd, iridescente, et salmonis colore subtincta.

Shell narrow-elliptical, transverse, inequilateral; valyes rather thin; beaks much
VOL. V.—I

34 ON THE NAIADES,

plicated; cardinal teeth double in both valves; lateral teeth straight; nacre splendidly
pearly, slightly salmon coloured, and beautifully iridescent.

Hab. China. Mrs Murchison.
My Cabinet.

Diam. °7, Length -8, Breadth 1-9 inches.

Shell narrow-elliptical, transverse, inequilateral, angular behind, and
slightly emarginate at basal margin; substance of the shell rather thin;
beaks and umbones beautifully plicated; umbonial slope subcarinate
and rough with the angles of the folds; posterior slope finely plicate ;
ligament yellow and narrow; epidermis dark green; cardinal teeth
double in both valves; lateral teeth straight ; anterior cicatrices distinct ;
posterior cicatrices confluent; dorsal cicatrices in the centre of the
cavity of the beaks; cavity of the beaks shallow; nacre rich, and splen-
didly pearly, slightly salmon coloured, and beautifully iridescent.

Remarks.—This splendid species I owe to the great kindness of
Mrs Murchison, the wife of the present learned president of the Geo-
logical Society of London. Among many fine and rare shells received
from her I found this, which appears not to have been before de-
scribed. It perhaps most resembles the U. ceeruleus (nobis), particu-
larly in the outline: it is, however, rather more transverse. It differs
greatly from the cwruleus in the number and size of the folds. ‘These,
behind the umbonial slope, are parallel to the ligament; while those on
the anterior margin are oblique. ‘The acute angles formed by the
folds on the umbonial slope are very remarkable. The inferior part
of the shell is free from folds: this may not, however, prove a constant
character. Its nacre is without exception finer than any I have ever
seen, and rich beyond description. ‘The folds being visible from the
interior, add greatly to its lustre.*

* Since writing these remarks 1 have seen several specimens of this shell in Europe. At
the Jardin des Plantes, Monsieur de Blainville showed me two or three specimens recently
received, and not yet placed in the cabinet. He considered the shell undescribed, until [
mentioned the name I had given it.

AND OTHER FAMILIES. 35

Unto Haystanus. Plate III. fig. 7.

Testa subrotundd, subventricosd, ad baseos marginem posteriorem dentatd ;
valvulis subcrassis ; natibus prominentibus ; epidermide luteo-fuscd levissimaque ;
radiis obsoletis ; dentibus cardinalibus in lobos divisis, lateralibus crassis rectisque ;
margaritd cacao colore tinctd.

Shell subrotund, slightly ventricose, dentate at posterior basal margin; valves scarcely
thick ; beaks elevated; epidermis yellowish brown and yery smooth; rays obsolete ;
cardinal teeth lobed ; lateral teeth thick and straight; nacre chocolate coloured.

Hab. Cumberland River. Professor Troost.
My Cabinet.
Cabinet of Mr Cooper.
Cabinet of Professor Troost, Nashville.

Diam. °6, Length 8, Breadth 1 inch.
Shell subrotund, nearly equilateral, slightly ventricose, dentate at
posterior margin, depressed before the umbonial slope ; substance of the
shell scarcely thick ; beaks thick and elevated; epidermis yellowish-
brown, very smooth and shining; rays obsolete; cardinal teeth lobed,
double in the left valve, single and rising from a pit in the right valve;
lateral teeth short, thick and straight; posterior and anterior cicatrices
both distinct; dorsal cicatrices situated within the cavity of the shell
on the plate between the cardinal and lateral teeth ; cavity of the beaks
deep and angulated ; nacre chocolate coloured and iridescent posteriorly.

Remarks.—It has been in my power to examine only four or five
specimens of this exceedingly interesting shell. In each of these there
is more or less of a dentate appearance, which is so unusual among the
Naiades that it may, perhaps with propriety, be said to belong to some
American species only. In the early stages of growth there is no den-
tate appearance. The U. sulcatus (nobis) and the U. arceformis
(nobis), are frequently furnished with this curious appendage. The
dentate variety, mentioned in my description of U. sulcatus, has been.
by Mr Say, erected into a separate species, under the name of ridi-
bundus ; in the propriety of which, however, I cannot agree with that
naturalist. In outline the present species resembles the U. subrotun-

36 ON THE NAIADES,

dus ; it is, however, more oblique, and in the epidermis more shining.
It is not so oblique as the sulcatus, but has a furrow anterior to the
umbonial slope similar to that species. In the epidermis it differs very
much, the sulcatus being finely wrinkled and finely rayed. In some
specimens the successive rows of teeth along the posterior margin cause
that portion of the shell to swell out, which gives it a rich and beauti-
ful appearance. It is, though small, among the most interesting of
our species. The specimen here represented, I owe to the kindness of
Mr Cooper. It is with pleasure I dedicate this species to my friend,
Isaac Hays, M.D., whose talents have been actively and successfully

engaged many years in the promotion of natural as well as medical
science.

Unio Hinpretuianvs. Pilate III. fig. 8.

Testa angusto-ellipticd, subcylindraced, valde transversd, inequilaterali ; valvu-
lis tenuibus ; dente cardinali in valvuld utraque unico, laterali nullo ; margarita
superne fuscd, inferne alba et iridescente.

Shell narrow-elliptical, subcylindrical, very transverse, inequilateral; valves thin;
cardinal teeth single in each valve; without lateral teeth; nacre, above brown, below
white and iridescent.

Hab. Ohio, near Marietta. Dr Hildreth.
My Cabinet.
Cabinet of Dr Hildreth.
Cabinet of the Academy of Natural Sciences.

Diam 55, Length -7, Breadth 1-6 inches.

Shell narrow-elliptical, subcylindrical, very transverse, inequilateral,
somewhat compressed at basal margin; substance of the shel! thin be-
hind, thicker before; beaks slightly elevated; ligament long and thin;
epidermis dark brown; cardinal teeth lobed, single in each valve, larger
and wider in the left valve; lateral teeth none; anterior and posterior
cicatrices both confluent; dorsal cicatrices in the centre of the cavity
of the beaks; cavity of the beaks shallow and tinged with dull purple ;
nacre white and iridescent.

AND OTHER FAMILIES. SH

Remarks. —Among the Uniones there is a group to which this species
naturally belongs. This group is characterized by the imperfection of
the hinge, the cardinal teeth being so immature as to present scarcely any
thing but lobes. Like the soleniformis it lives under stones and other
protected places. In the present species the tooth of the right valve
shuts before that of the left, and the lateral teeth, if not entirely want-
ing, are obsolete. The group, as far as I know it at present, consists
of the U. oriens (nobis), U. soleniformis (nobis), and the present species.
In size and outline of the margin, this species resembles the U. iris
(nobis). It has not, however, the brilliant nacre, nor the fine rays of
that species, and in the conformation of the teeth it differs very much.
Some individuals vary from the cylindrical form, being somewhat com-
pressed. As a mark of respect for the talents of Dr Hildreth, and his
assiduity in promoting a knowledge of the natural history of his vici-
nity, I dedicate this species to him.

Unio Scuooucrartensis. Plate III. fig. 9.

Testa subrotundatd, subequilaterali, compressa, post clivum umboniale subtu-
berculatd ; valvulis subcrassis; natibus prominentibus ; epidermide fulvd, lato-
radiata ; dentibus cardinalibus prominentibus, lateralibus laminatis rectisque ;
margarita alba et iridescente.

Shell subrotund, nearly equilateral, compressed, slightly tuberculated behind the
umbonial slope ; valves rather thick; beaks elevated; epidermis yellow with broad
rays; cardinal teeth elevated ; lateral teeth straight and lamellar; nacre pearly white
and iridescent.

Hab. Fox River of Green Bay. Mr Schoolcraft.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam. °7, Length 1:1, Breadth 1-3 inches.

Shell subrotund, somewhat angular at posterior dorsal margin, nearly
equilateral, compressed, slightly tuberculated posterior to umbonial
slope; substance of the shell rather thick ; beaks elevated; ligament
short ; epidermis smooth, somewhat yellow, with several broad green
rays—that over the centre of the disk being broadest; cardinal teeth

VOL. Y.—K

38 ON THE NAIADES,

elevated and cleft in the left valve, single and rising from a pit in the
right; lateral teeth elevated, straight and lamellar; anterior cicatrices
distinct; posterior cicatrices confluent; dorsal cicatrices within the
cavity of the shell on the base of the cardinal tooth; cavity of the
beaks angular and deep; nacre pearly white and iridescent.

Remarks.—Among the many fine shells presented to the Acade-
my of Natural Sciences by Mr Schoolcraft from the region of the
upper lakes, there was a single specimen of the present species. It
does not seem referable to any described species, and I have conse-
quently been induced to give it a separate place in the genus. It re-
sembles most the U. rubiginosus (nobis) in outline, but differs from it
in being more rounded on the inferior and posterior portions of the
margins, as well as in the cardinal tooth being more elevated and more
deeply cleft. In the rays it differs very much from that species. In
this specimen they are very remarkable, there being a very distinct
broad one anterior to the umbonial slope, covering one third of the side
of the disk, and two smaller, posterior to the umbonial slope. When
there is but a single specimen to describe from, it should be remem-
bered that many characters are not permanent, and I should not be
surprised if specimens of this species be found without a single ray,
although they are so striking in this. The tubercles, which are so
indistinct, may in other specimens be more distinct and more numerous.
In this case it will approach so closely to the asperrimus (nobis), that
it may prove to be only a variety.

Unto Geometricus. Plate IV. fig. 10.

Testa trapezoidali, valde inequilaterali, transversd, compressd ; valvulis tenui-
bus; natibus prominulis, rugis concentricis; dentibus cardinalibus in valvula
utrdque obliquis duplicibusque, lateralibus subrectis ; margarita purpured.

Shell trapezoidal, very inequilateral, transverse, compressed; valves thin; beaks

slightly prominent and concentrically wrinkled; cardinal teeth oblique and double in
both valves; lateral teeth nearly straight ; nacre purple.

Hab. Bayou Teche, Louisiana. W. M. Stewart.

Symphynta globosa

Unto qeometricus :
v Unie Tartuanus

Drawn by Drayton

*%

AND OTHER FAMILIES. 39

My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Cabinet of Mr Stewart.

Cabinet of Mr Hyde.
Diam. °9, Length 1-4, Breadth 2-7 inches.
Shell trapezoidal, very inequilateral, transverse, compressed, angular
behind ; substance of the shell rather thin ; umbonial slope subcarinate ;
beaks slightly prominent, placed near the anterior margin and concen-
trically wrinkled; carina much elevated; ligament long, narrow and
nearly straight; epidermis dark brown, wrinkled and sometimes ob-
scurely rayed ; cardinal teeth oblique and double in both valves; lateral
teeth nearly straight and lamelliform ; anterior cicatrices distinct, pos-
terior cicatrices confluent; dorsal cicatrices situated in the centre of
the cavity of the beaks; cavity of the beaks shallow: nacre purple and

iridescent.

Remarks.—This interesting species is one of the collection made by
Mr Stewart in the Bayou Teche. It is a very distinct and beautiful
species. Its form is more like a trapezium than that of any other spe-
cies with which I am acquainted. It resembles most the U. compla-
natus (Soland.). It differs from it, however, in its remarkable outline,
in its teeth, in the concentric wrinkles of the beaks, and in the beaks
being placed nearer to the anterior margin. The angle of the poste-
rior margin is also more acute. In the deep brown colour of the epi-
dermis and in outline of the margin it approaches the U. obesus (nobis).
It is, however, much less inflated.

Unio Tarrianus. Plate IV. fig. 11.

Testa subtriangulari, obliqua crassdque ; valvulis antice crassioribus ; dentibus
cardinalibus grandibus et elevatis, lateralibus crassis et subcurvis ; margarita
alba.

Shell subtriangular, thick and oblique ; valves thicker anteriorly ; cardinal teeth large
and elevated ; lateral teeth thick and slightly curved; nacre pearly white.

40 ON THE NAIADES,

Hab. Alabama River. Judge Tait.
My Cabinet.

Diam. 1:1, Length 1:5, Breadth 1-5 inches.

Shell subtriangular, thick, oblique. depressed anterior to umbonial
slope ; substance of the shell very thick anteriorly and thin posteriorly ;
beaks very thick and much elevated ; epidermis dark brown and wrin-
kled; cardinal teeth large, crenate and deeply cleft in the left valve,
and emerging from a pit in the right; lateral teeth thick, slightly curved
and nearly parallel with the line of the cardinal teeth; anterior cica-
trices distinct, the great one forming a deep pit; posterior cicatrices
distinct, the smaller one being placed at the end of the lateral tooth;
dorsal cicatrices situated on the plate between the cardinal and lateral
teeth; cavity of the beaks shallow; nacre pearly white.

Remarks.—There is no species which this so closely resembles as
the scalenius (Rafin.). It is, however, less oblique and more expanded
along the posterior basal margin, and the posterior margin forms a more
obtuse angle. It is with great pleasure I name it after my friend,
Judge Tait of Claiborne, Alabama, to whom science is greatly indebted
for his exertions in making known the natural history of his vicinity.

Unto tacteouus. Plate VIII. fig. 19.

Testa ellipticd, transversd, inequilaterali, subinflatd ; valvulis subcrassis ; nati-
bus radiatis, plicis brevibus ; dentibus cardinalibus in valvulé utrdque duplicibus
longisque ; lateralibus longis, a cardinalibus separatis ; margarita lacteold.

Shell elliptical, transverse, inequilateral, somewhat inflated ; valves not thick ; beaks
having short radiating folds; cardinal teeth long and double in both valves ; lateral
teeth long and separate from the cardinal teeth; nacre pearly and milk white.

Hab. Rio de la Plata.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of W. Hyde.
Unio delodonta? Lam.

AND OTHER FAMILIES. 41

Diam. 1-2, Length 2, Breadth 3-2 inches.

Shell elliptical, transverse, inequilateral, somewhat inflated ; substance
of the shell not thick; beaks rounded, having short radiating folds;
ligament rather short; epidermis dark brown and wrinkled; cardinal
teeth long, oblique, nearly parallel with the margin and double in both
valves; lateral teeth long, slightly curved and separated from the car-
dinal teeth by the absence of a plate; anterior and posterior cicatrices
both confluent; dorsal cicatrices situated across the cavity of the beaks ;
cavity of the beaks rounded and not deep; nacre very pearly, milk
white, iridescent behind.

Remarks.—I am indebted to the kindness of Dr Ward of Salem, for
a perfect specimen of this species. In outline it approaches the
U. marginalis (Lam.), but is less transverse. In the characters of
its teeth it closely resembles that species. It differs from it in being
more inflated, more wrinkled and in having a thicker nacre. In the
possession of radiated folds on the beaks it differs altogether.

On the base of the cardinal tooth, near to the great cicatrix, there is
a small deeply impressed cicatrix, resembling in its characters that of
the Hyria avicularis (Lam.), mentioned at page 67, Vol. IV.

The specimen here figured belongs to the fine cabinet of Mr Hyde.

SympuynorTa GLoposa. Plate IV. fig. 12.

Testa valde globosd, inequilaterali, pellucida ; valvulis tenuiculis, natibus ro-
tundissimis, incurvis ; epidermide luted, levissimd ; dentibus cardinalibus lami-
natis, lateralibus elevatis et laminatis ; margarita alba et tridescente.

Shell very globose, inequilateral, translucent ; valves rather thin ; beaks very round,
incurved ; epidermis very smooth and pale yellow; cardinal teeth lamellar ; lateral
teeth elevated and lamellar ; nacre pearly white and iridescent.

Hab. River Ohio, 150 miles below Louisville. Col. Long.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Peale’s Museum.
VoL. ¥.—L

42 ON THE NAIADES,

Diam 2:4, Length 2°5, Breadth 3:5 inches.

Shell very globose, inequilateral, translucent, very smooth and
bright; connate before and behind the beaks; substance of the shell
rather thin; beaks very round, incurved ; epidermis very smooth, and
pale yellow or straw colour; umbones very round; cardinal teeth
very lamellar, elevated, double in the right valve, and very crenate and
single in the left; the line of the lateral and cardinal teeth form two
curves; anterior cicatrices distinct; posterior cicatrices confluent;
dorsal cicatrices situated in the cavity of the beaks on the under side
of the cardinal teeth; palleal cicatrix deeply impressed; cavity of
the beaks very round and very deep; nacre thicker near the margin,
beautifully pearly white and iridescent.

Remarks.—We owe to Col. Long and Mr T. Peale the knowledge
of this singular and distinct species. Without a tubercle and almost
rayless, for those on the posterior slope are obsolete, it is among the
most beautiful and interesting species known. The Academy is in
possession of four fine specimens, making a complete suite of different
ages. Three of them are perfect enough to display the character of
this genus, Symphynota, notwithstanding their great globosity. It
is more capacious than any of the (aiades I have seen, and the light
yellow or straw coloured epidermis is very peculiar—in form it most
resembles, perhaps, the Unio occidens (nobis), but it has no rays. In
the younger individuals there is a transverse rib-like appearance which
I have noticed in no other species of the family.

SympnynotTa Wooprana. Plate V. fig. 13.

Testa subpentagond, postice angulatd, super umbones turgidd, inequilaterali,
transversd ; valvulis tenuibus ; epidermide tenebroso-fuscd et obscuro-radiatd ;
natibus undulatis ; margarita albd et iridescente.

Shell subpentagonal, angular behind, turgid over the umbones, inequilateral, trans-
verse ; valves thin; epidermis dark brown and obscurely rayed ; beaks undulated ;
nacre pearly white and iridescent.

Symphynota

Woodiana.

PE envi

Jol. 5.

Symphynota

magnifica.

ar eae,
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AND OTHER FAMILIES. 43

Hab. China. W. W. Wood.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam. 1:5, Length 2-2, Breadth 3:5 inches.

Shell subpentagonal, angular behind, transverse, inequilateral, irre-
gularly swollen over the umbones, slightly compressed somewhat be-
fore and below the umbones, posterior slope carinate; substance of the
shell thin; epidermis wrinkled, dark brown with obsolete rays; liga-
ment long and somewhat thick; beaks slightly inflated and undulated ;
cicatrices scarcely perceptible posteriorly, more deeply impressed ante-
riorly; cavity of the beaks shallow; cavity of the disk impressed im-
mediately under the umbo; nacre pearly white and iridescent.

Remarks.—This species was first, I believe, brought to this city from
Canton by Mr Wood* about five years since. To him I owe the first
specimen I have seen. A younger and fine specimen I owe to the
kindness of an estimable friend and accomplished conchologist, Mrs
Corrie, who sent it to me from England about two years since, with a
label “ From China.” It closely resembles the preceding species in
many characters. All the specimens, however, which I have seen,
perhaps half a dozen, retain the distinctive characteristics—the greater
transverseness—the subpentagonal form—the slight compression ante-
rior to the umbones—the dark epidermis—the absence almost entirely
of rays and its want of a rich nacre—in all these it differs from the mag-
nifica herein described. It is usually larger than the specimen figured.

SyMPHYNOTA MAGNIFIcA. Plate V. fig. 14.

Testa subrotundd, prope nates valde inflata, inxquilaterali, postice obtuso-
angulatd ; valvulis tenuibus ; epidermide luted, multis radiis viridibus ; natibus

* On my return from Europe I found a box of shells sent to me by Mr Wood from Canton,
in which were several specimens of a tuberculated Unio, which, on examination, I perceived
immediately to be anew species, which the distinguished naturalist, John Edward Gray, Esq.,
of London, did me the honour, while in that city last June, to name Leanus.

44 ON THE NAIADES,

inflatis, prope apices undulatis ; cicatricibus vie cernendis ; margaritd pulchrd et
iridescente.

Shell subrotund, much inflated near the beaks, inequilateral, obtusely angular behind;
valyes thin; epidermis yellow, with numerous green rays ; beaks inflated, near the tip
undulated ; cicatrices scarcely perceptible; nacre beautifully pearly and iridescent.

Hab. China. W. W. Wood.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia,
Cabinet of Mr Hyde.

Diam. 1°6, Length 2:3, Breadth 3:4 inches.

Shell subrotund, much inflated in the region of the beaks, inequi-
lateral, connate before and behind the beaks, obtusely angular behind,
rounded before, posterior slope carinate; substance of the shell thin;
epidermis smooth, yellow with numerous beautiful green rays over the
whole disk, which are darker on the posterior part and obsolete on the
umbones; ligament long and thin; beaks inflated and terminated with
about six nearly parallel undulations; teeth, none; cicatrices scarcely
perceptible ; cavity of the beaks shallow and rounded ; nacre beautifully
pearly and highly iridescent, sometimes tinged with salmon and pink.

Remarks.—Several specimens of this species have been within a few
years received from Canton, and Mr Wood, to whom I owe one of
mine, informed me that he believes it to be a native of that country, and
most probably dwelling in the waters of the neighbourhood of Canton.
It is certainly among the most beautiful of the genus which has come
under my notice, and is remarkable for its great area, its inflation of
the region of the beaks, its smooth epidermis, its splendid rays and ex-
quisitely beautiful nacre, which no pencil can imitate. I have it of
several different ages—when very young it is less rotund, being some-
what trapezoidal, the dorsal margin nearly straight and the rays obso-
lete. The specimen figured is not half the size of the largest specimen
in my cabinet, but I have chosen it for its great perfection in having
the valves completely connate before and behind the beaks.

. -_ = ad a =
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PL .VI Vol.5.

Key
Ne re er
Posen

Anadonta tneerta .

Anadonta, Ferussaciana

DE ;
Drawn on stone by J Drayton i, 7 D Brae r

AND OTHER FAMILIES. 45

AnoponTA Frrussacrana. Plate VI. fig. 15.

Testd subcylindraced, inequilaterali, inflata; margine dorsali sub natiwm
apices curva ; valvulis tenuibus ; epidermide fulgidd, obsolete radiatd, olive colorem
tenebrosum habente ; natibus prominulis, binis ternisve undulis exiguis ad apices ;
cicatricibus conspicuis; margarita ceruleo-alba et iridescente.

Shell subeylindrical, inequilateral, inflated ; dorsal margin curved immediately
under the point of the beak ; valves thin ; epidermis dark olive, shining, with obsolete
rays ; beaks somewhat prominent with two or three small undulations at tip ; cicatrices
perceptible; nacre bluish white and iridescent.

Hab. Ohio River, near Cincinnati. T. G. Lea.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Mr Nicklin.
Cabinet of Professor Vanuxem.
Cabinet of the American Philosophical Society of Philadelphia.
Diam. 1-4, Length 1:8, Breadth 3-5 inches.
Shell subcylindrical, inequilateral, much inflated, more angular
behind than before; dorsal margin curved immediately under the
point of the beak; basal margin disposed to be emarginate ; substance
of the shell thin; epidermis dark olive, shining, with numerous obso-
lete rays, near the beaks lighter and destitute of rays ; ligament rather
short and thin; beaks somewhat prominent with two or three small
undulations at tip; cicatrices perceptible; cavity of the beaks shallow:
cavity of the disk deep and rounded ; nacre bluish white and iridescent.

Remarks.—This species was received with the 2. incerta, here-
in described, from the Ohio river. It differs from that species in
having prominent beaks, in being more cylindrical, in its dark colour,
and in the curve which exists immediately under the beaks, in which
it resembles the 2. areolus (Swainson). In the latter this curve is so
strong and thick as to resemble an incipient tooth. In young speci-
mens the epidermis is more on the yellow, and the rays greenish and
bright.*

* Since the above description was made and the figure printed, I am in possession of sev-
eral specimens from Illinois, beautifully and very distinetly rayed.
VOL. V.—M

46 ON THE NAIADES,

ANODONTA INCERTA. Plate VI. fig. 16.

Testa lato-ellipticd, postice subangulatd, inflata, margine dorsali subrecté ; val-
vulis tenuissimis ; epidermide subviride, obsolete radiata ; natibus complanatis et -
minute undulatis ; cicatricibus viz cernendis ; margaritd ceruleo-albé et iridescente.

Shell wide-elliptical, subangular behind, inflated, nearly straight on the dorsal mar-
gin; valves very thin; epidermis greenish with obsolete rays, beaks flattened and
minutely undulated ; cicatrices scarcely perceptible ; nacre bluish white and iridescent.

Hab. Ohio River near Cincinnati. 'T. G. Lea.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Professor Vanuxem.
Cabinet of P. H. Nicklin.
Diam. 1:2, Length 1-5, Breadth 3-2 inches.
Shell wide-elliptical, subangular behind, inequilateral, inflated, dor-
sal margin nearly straight, rounded before; substance of the shell very
thin; epidermis very smooth, green and olive green with obsolete
rays, three being more distinct on the posterior part of each valve ; lig-
ament Jong and thin; beaks flattened, minutely undulated near the
tip which terminates with a minute point from which an indistinct
line runs towards the posterior margin ; cicatrices scarcely perceptible ;
cavity of the beaks scarcely perceptible; cavity of the disk deep and
rounded; nacre bluish white and iridescent.

Remarks.—Among the earliest shells I procured from the Ohio,
many years since, were several specimens of this fragile Anodonta.
The difficulty of separating the species of a genus with so few tangible
characters induced me to lay this aside with some other species until
more leisure would permit a thorough examination. It perhaps most
closely resembles the .2. cataracta of Say, but differs from it peculiarly
in the flatness ef the beaks. It is generally more inflated, particu-
larly near the umbonial slope. Itresembles the 4. Ferussaciana (nobis),
the description of which see. The young differ from the old in being
much compressed and in having rays only on the posterior part of the
shell, where the three on each valve are distinctly visible—they are

AND OTHER FAMILIES. A7

also more straight on the dorsal margin. The smoothness and polish,
as well as the brightness of the green of some of the specimens are
very remarkable.

AnoponTAa STEWARTIANA. Plate VI. fig. 17.

Testé rotundato-ovatd, valde inflata ; valvulis pertenuibus ; epidermide subas-
perd, tenebroso-viridi, natibus prominentibus, apicibus granulatis ; cicatricibus
subobsoletis aut viz perspicuis ; margarita ceruleo-albd.

Shell rotundo-ovate, much inflated ; valves very thin; epidermis roughish, olive
green; beaks prominent and granulate at tip; cicatrices scarcely perceptible ; nacre
bluish white.

Hab. River Teche, Louisiana. W. M. Stewart.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Mr Stewart.

Diam. 1:8, Length 2, Breadth 3-1 inches.

Shell rotundo-ovate, much inflated, subangular behind; dorsal line
slightly curved; substance of the shell thin; epidermis somewhat
rough, olive green and obsoletely rayed; beaks prominent, granulate
at tip in a short double series; cicatrices scarcely perceptible; cavity
of the beaks deep and incurved ; cavity of the disk deep and rounded;
nacre bluish white and iridescent, sometimes tinged with salmon co-
lour about the region of the beaks.

Remarks.—I owe this species with numerous others to my friend
Mr Stewart who procured and gave it to me more than two years since.
I did not then describe it, although I believed it to be new, intending
it to accompany some others which are now embodied in this memoir.
It is an interesting species, being much inflated—the young specimens
approached the globose form. It is most similar in form to the
gibbosa (Say), but is perhaps less inflated, does not possess a polished
epidermis, and has granulations at the termination of the beaks, while
the gibbosa has undulations. The inflation of the Sfewartiana is more

48 ON THE NAIADES,

spherical, the other is gibbous. ‘The posterior slope of the young
specimen is decorated with six distinct green rays, there being three
on each valve.

AnoponTAa PALNA. Plate VII. fig. 18.

Testa subovatd, inequilaterali, subcompressa ; valvulis subcrassis ; epidermide
olivaced et obsolete radiataé ; natibus prominentibus ; apicibus granulatis ; cica-
tricibus perspicuis ; margaritd albdé ; sed in natium cavo interdum colore salmo-
nis tinctd,

Shell subovate, inequilateral, rather compressed ; valves somewhat thick; epidermis
olive with obsolete rays; beaks prominent and granulate at tip ; cicatrices perceptible ;
nacre white, sometimes salmon in the cavity of the beaks.

Hab. Bear Grass Creek, near Louisville. Mr T. H. Taylor.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Mr Ronaldson.

Diam. 2°3, Length 3:1, Breadth 5-6 inches.

Shell subovate, inequilateral, rather compressed, subangular behind ;
dorsal line slightly curved; substance of the shell thick; epidermis
smooth, olive to dark green, brighter on the beaks; rays obsolete ;
ligament long and thick; beaks elevated, granulate at tip; cicatrices
perceptible; cavity of the beaks rather deep and rounded; cavity of
the disk somewhat flattened ; nacre white, sometimes salmon coloured
in and about the cavity of the beaks.

Remarks.—This species of Anodonta offers quite a large area in
the circumference of the disk. Some specimens are, however, more
transverse than the one here described. It has a predisposition to
salmon colour in the region of the cavity of the beaks, and this is
sometimes of a very deep tint. The colour is irregularly distributed,
sometimes quite in spots, and a roughness, apparently a disease, often
accompanies it and produces a carious state of the nacre. It perhaps
most closely resembles the 2. cataracta (Say); but is usually less in-
flated, is thicker in the substance of the shell, and less transverse.

PL. VIE Vol.5

ti | Perera

Anadonta plana

Browns Lrth Drawn bry J. Drayton

at ei Nl

coe

AND OTHER FAMILIES. 49

Heuic1na Lens. Plate XIX. fig. 56.

Testd pared, lenticulari, supra luted, subtus rufa; anfractibus tribus, quorum
inferiori carinato ; spird plano-conveaxd ; apertura dilatatd ; labro crasso ; columella
subcallosd et luteold.

Shell small, lenticular, yellow above and red below; whorls three, inferior one
carinate ; spire plano-convex ; aperture dilated ; outer lip thick ; columella thinly coated
and yellowish.

Hiab. Feejee Islands. W.W. Wood.

My Cabinet.
» Diam. 5-20ths, Length 4-20ths of an inch.
The smaller figure is of the size of nature.

Remarks.—The lenticular form and sharp carina of the body whorl
distinguish this species. Within it is orange, and about the base of
the shell there is a disposition to yellow.

HELIcINA PULCHERRIMA. Plate XIX. fig. 57.

Testd subviridi, subglobosd, crassd, minute striata; anfractibus quaternis,
quorum infimo fascia albo-fuscd induto; spira obtusd; apertura dilatatd ; labro
albo et reflexo ; columelld callosd, albd, fulgenti, tuberculo parvo ad basim.

Shell subglobose, greenish, thick, finely striate ; whorls four, the body whorl having
an indistinct white and brown band; spire obtuse ; aperture dilated ; outer Jip white and
reflected ; columella white, thickly coated and shining, with a small tubercle at the
bottom.

Hab. Java?
My Cabinet.
Diam. ‘8, Length -7 of an inch.

Remarks.—This is perhaps the finest species yet known of the
VOL. V.—N

50 ON THE NAIADES,

genus. It is remarkable for its size and weight, and the strong and
wide callus on the columella. Under the epidermis it varies from a
dark orange to lemon yellow. A depauperated specimen in my pos-
session would scarcely be recognized as the same species, owing to the
density of the orange colour. The apex of the perfect shell, having
but a thin epidermis, presents an orange appearance,—this colour may
also be observed on the inside of the shell. At the base of the colum-
ella there is an obsolete tubercle. The band sometimes consists of a
single white line only. It is believed these specimens formed part of
the collection brought from Java by Mr Shillaber.

HELICINA yirGINEA. Plate XIX. fig. 58.

Testa subconicd, apice acutd, subtus inflata, crassd, transversim multisulcatd ;
anfractibus senis; spira elevatd; aperturd valde dilatata; labro effuso; colu-
mellé subcallosa.

Shell subconical, acutely pointed, inflated below, thick, with many transverse fur-
rows ; whorls six ; spire elevated ; aperture much dilated ; outer lip effuse ; columella
thinly coated.

Hab. Java?
Helicina striata? Lam.
My Cabinet.
Diam. °8, Length -8 of an inch.

Remarks.—This species came in the same collection as that de-
scribed last. It is nearly of the same diameter. It differs from it
altogether inform and colour. It is remarkable for its acutely pointed
apex, its milk-white appearance, and its numerous furrows. The
outer lip may, with propriety, be said to be effuse rather than re-
flected.

AND OTHER FAMILIES. 51

Hewrx muscarum. Plate XIX. fig. 59.

Testé globosd, crassa, politd, longitudinaliter nitide striata, subfuscd ; maculis
numerosis irregularibus minutis, et fasciis albis subnigris e¢ fuscis indutd ; an-
Sractibus ternis; spird rotundatd ; apice albd; apertura subrotundd; labro
acuto, intus crassescenti ; labio subrufo ; columella levi albdque.

Shell globose, thick, polished, longitudinally and finely striated, light brown, fur-
nished with numerous irregular minute spots, and blackish brown and white bands;
whorls three ; spire rounded ; apex white; aperture nearly round; right lip sharp,
growing thicker within ; left lip light red ; columella smooth and white.

Hab. Society Islands, Pacific Ocean. Lieutenant Dornin.
My Cabinet.
Diam. °8, Length -7 of an inch.

Remarks.—This curiously and elegantly painted shell I owe to Lieu-
tenant Dornin, who, when on board the sloop of war Vincennes on
her voyage round the world, very kindly collected for me many rare
and fine specimens. It is eminently distinguished by its compound
band, its globosity, and its innumerable minute spots. ‘The columella
is somewhat thickened by a dark pink deposit.

HeEwix purruracuna. Plate XIX. fig. 60.

Testd obtuso-conicd, crassd, inferne planulatld, politd, longitudinaliler minute
striald, superne luted et fusco-virgatd, inferne luted, in medium anfractum ob-
scuro-fasciald, subsuturam maculata, imperforatd ; anfractibus quinis ; spird
obtuso-conicd ; apertura ovata, intus purpured; labro reflexo, prope basim ma-
Jori ; columella levi, ad basim subconcava.

Shell obtusely conical, thick, flattened below, polished, minutely and longitudinally
striate, above yellow and striped with brown, below yellow, obscurely banded on the
middle of the whorl, irregularly spotted on the inferior part of the suture, imperforate ;
whorls five; spire obtusely conical; aperture oval, purple inside; outer lip sub-
reflected, enlarged towards the base ; columella smooth and impressed at base.

52 ON THE NAIADES,

Hab. Java?
My Cabinet.
Diam. -9, Length °6 of an inch.

Remarks.—The solidity, smoothness and purple colour of this spe-
cies, which is supposed to have been of Mr Shillaber’s collection, will
serve to distinguish it. Like the mamilla, herein described, it has a
thick lip and is impressed at the base of the columella. ‘The two
specimens which I have differ much in the arrangement of colour.
In one the inferior portion is almost white, and a dark interrupted band
encircles the middle of the whorl.

Hewix ovum recut. Plate XIX. fig. 61.

Tesid super et subtus planulatd, colore columbino tinctd, minutis irregularibus
maculis numerosis, imperforaté; anfractibus quaternis; spird valde depressd ;
aperturd subovald, intus purpurascenti ; labro acuto, subreflexo ; columella levi,
ad basin subconcavda.

Shell flattened above and below, dove coloured, with numerous irregular minute dots,
imperforate ; whorls four; spire much flattened; aperture suboval, purplish inside ;
outer lip somewhat reflected but sharp; columella smooth, at base impressed.

Hab. Java?
My Cabinet.
Diam. °8, Length -4 of an inch.

Remarks.—The very peculiar colour and the minute dots of this
beautiful and interesting species eminently distinguish it from all other
species which haye come under my notice. The line of the superior
part of the lip is almost parallel with the corresponding inferior part,
and the outer posterior is consequently more round. In my specimens
there are two very indistinct bands, rather lighter than the ground.
In colour it greatly resembles a spotted small egg of a bird. It is sup-
posed to have come from Mr Shillaber’s collection. -

AND OTHER FAMILIES. 53

Heix monoponta. Plate XIX. fig. 62.

Tesla superne subconicd, inferne inflald, levi, alba, fasciis duabus fuscis, tm-
perforata; anfractibus ternis ; spira oblusa; apertura subrotundd ; labro acuto,
subreflexo, subtus unico dente induto ; columella laxvi.

Shell subconical above, inflated below, smooth, white, with two brown bands, im-
perforate ; whorls three ; spire obtuse ; aperture nearly round; outer lip somewhat re-
flected but sharp, having a single tooth on the lower limb ; columella smooth.

Hab. Java?
My Cabinet.
Diam. 9-20ths, Length 7-20ths of an inch.

Remarks. —The two brown bands and single tooth of this species,
together with the absence of an umbilicus, may serve to distinguish it.
The superior termination of the lip is bent.down towards the base of the
columella. It is supposed to be from the collection of Mr Shillaber.

Hewtx cycLtostomorsis. Plate XIX. fig. 63.

Testa subglobosd, superne depressa, inferne inflata, longitudinaliter et minute
striata, pellucida, corned, late umbilicatd ; anfractibus quaternis ; spira depressé ;
aperturd subcirculart ; labro crasso et reflexo ; columella levi, ad basin crassescenti.

Shell subglobose, depressed above, inflated below, longitudinally and minutely striate,
translucent, horn coloured, widely umbilicate; whorls four ; spire depressed ; aperture
nearly a circle; outer lip thick and reflected ; columella smooth, at the base thickened.

Habuieekk<

My Cabinet.
Diam -9, Length -6 of an inch.

Remarks.—In its aperture this species has a strong resemblance to

a Cyclostoma. 'The superior and inferior portions of the lip do not,

however, join by one-fifth of a circle—the resemblance is strong in the
VOL. V.—o0

54 ON THE NAIADES,

thickness and reflection of the lip. The last whorl is very round—
the umbilicus large and partly covered.

Henix Mamma. Plate XIX. fig. 64.

Testa solid, elevata, obtuso-conica, inferne rotundata, imperforata, colore colum-
bino tincta, longitudinaliler nitide striata, fasciis duabus obsoletis indutd, apice
subrufo ; anfractibus quinis, rotundatis ; spird exsertd ; apertura subrufa, ovate ;
labro subreflexo, crasso, prope basin majori ; columella levi, ad basin subconcava.

Shell solid, elevated, obtusely conical, rounded below, imperforate, dove coloured,
transversely and finely striate, with two obsolete bands, pink at the apex ; whorls five
and rounded ; spire elevated ; aperture pink, oval ; outer lip somewhat reflected, thick,
enlarged towards the base; columella smooth, at the base impressed.

Habana:
My Cabinet.
Diam. °8, Length -7 of an inch.

Remarks.—I have rarely met with a more beautiful and interesting
species of the genus than the above. It is eminently distinguished by
its solidity, its thick, smooth and beautifully coloured lip, its fine deli-
cate colour, and its elevated and red tipped spire. The columella is
somewhat thickened and deeply impressed at the base.

It is to be regretted that the habitat of this species is not known.
It was met with accidentally at a dealer’s.

HELIX DIAPHANA. Plate XIX. fig. 65.

Testa lata, superne depressd, inferne inflata, longitudinaliter et nilide striata ;
subluted, obscure bifasciata super medium anfractum, umbilicatd ; anfractibus
guaternis ; spird planulata ; aperturd magna et subrotundd ; labro simplict ; colum-
ella brevissima levique.

Shell wide, depressed above, inflated below, longitudinally and finely striate, pale
yellow, obscurely banded above the centre of the whorl, umbilicated; whorls four ;

AND OTHER FAMILIES. 55

spire flattened ; aperture large and nearly round ; outer lip simple ; columella very short
and smooth.

Blass 25
My Cabinet.
Diam. 1-4, Length -7 of an inch.

Remarks.—This species has a strong resemblance to 7. citrina. It
may be distinguished from that species by its colour, which is more
pale, being almost a light horn colour; by its being more flattened, and
by its band, which is white bordered on each side by a delicate brown
line. ‘The umbilicus is small.

Hewvix Hrwanana. Plate XIX. fig. 66.

Testa sinistrosa, subcarinata, tenui, subdiaphand, umbilicata, superne subcon-
vera, inferne inflata, longitudinaliter et transversim minute striata, superne fusco-
luted, inferne fusca, prope carinam tenebrosiori ; anfractibus quaternis ; spird
obtusa ; apertura late rotundata ; labro simplict et acuto; columella brevi.

Shell sinistral, subcarinate, thin, translucent, umbilicated, obtusely convex above,
inflated below, longitudinally, transversely and minutely striate, superior part brown-
ish yellow, inferior part brown, being more intense near the carina ; whorls four ; spire
obtuse ; aperture widely rounded ; outer lip simple and sharp ; columella short.

Hab. Himalaya Mountains. Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Mr Hyde.
Diam. 1+1, Length -7 of an inch.

Remarks.—In the splendid collection of objects of natural history
brought from India and other countries by Dr Burrough was this spe-
cies, which Dr B. procured himself among the Himalaya mountains.
It is easily distinguished from any species I am acquainted with, and
approaches most closely to the HZ. levipes(Fer.). Its sinistral opening,

56 ON THE NAIADES,

its translucency, and its colours are very characteristic. On the infe-
rior part of the carina, which is obtuse, the brown colour is more in-
tense—on the superior part the yellow is brightest.

Hetix vesica. Plate XIX. fig. 67.

Testa tenui, pellucida, superne elevatd et fusco-luted, inferne inflata albaque,
transversim minute striata, umbilicald, anfractibus quinis ; spird obluso-conicéd ;
apertura subrotunda ; labro tenui et reflexo, inferne crassescenti ; columella levi.

Shell thin, transparent, elevated and brownish yellow above, inflated and white be-
low, longitudinally and minutely striate, umbilicated; whorls five; spire obtusely
conical ; aperture nearly round ; outer lip thin and reflected, on the lower part slightly
thickened ; columella smooth.

Habs co...
My Cabinet.

Diam. -7, Length -5 of an inch.

Remarks.—This species is peculiarly transparent, and very strongly
resembles the cuticle of a blister or the bladder of a fish. This char-
acter, and its pale brownish-yellow superior portion, and white inferior
portion, together with its longitudinal striz, eminently distinguish it.
The lower part of the reflected lip is so much thickened as almost to
form a tooth.

Heurx cincta. Plate XIX. fig. 68.

Testa sunerne depressd, inferne inflata, longitudinaliter striata, umbilicatd,
rufo-fuscd, fasciam fuscam aut nigram super medios anfractus habente ; anfrac-
tibus qualernis ; spird plunulatd, aperturd subrotundatd ; labro simplici ; colum-
ella lzxvi.

Shell depressed above, inflated below, longitudinally striate, umbilicated, reddish
brown, with a dark brown or black band above the middle of the whorls ; whorls four ;
spire flattened ; aperture nearly round ; outer lip simple ; columella smooth.

AND OTHER FAMILIES. a |

Hab. Jaya?
My Cabinet.
Diam. -9, Length -6 of an inch.

Remarks.—The fine reddish-brown ground and intensely dark band
distinguish this fine Helix. In my specimen, which is the only one I
have seen, the inferior margin of the band has, adjoining it, an obscure
band, of a tint somewhat lighter than the ground. It should be ob-
served, that when other specimens may be examined, the bands may
not prove so regular as in the present specimen. Around the umbili-
cus the colour is more pale.

Hexix Wooprana. Plate XIX. fig. 69.

Testa supra obtuso-conicd, inferne inflata, longitudinaliter et nitide striata,
albidd, pellucida, fascia unicd in medium anfractum, late umbilicatd; anfractibus
qualernis ; spira obtusd, apertura rotundatd latdque; labro reflexo; columella levi.

Shell obtusely conical above, inflated below, longitudinally and finely striate, pale
and translucent, with a single band on the centre of the whorl, widely umbilicate ;
whorls four; spire obtuse ; aperture wide and round ; outer lip reflected; columella
smooth.

Hab. China near Canton. W. W. Wood.
My Cabinet.
Cabinet of Mr Hyde.
Cabinet of P. H. Nicklin.
Diam. -6, Length °4 of an inch.

Remarks.—Among a number of fine shells taken by Mr Wood, who
devoted himself much to natural history during some years’ residence
in China, was this species and the globula herein described, both from
the neighbourhood of Canton. It may be distinguished by its brown
band, its round aperture and enlarged umbilicus.

YOL. V.—P

58 ON THE NAIADES,

®

Hexix cuopunas. Plate XIX. fig. 70.

Testa globosd, tenebroso-corned, pellucida, umbilicatd, longitudinaliter striata ;
anfractibus quinis; spird obtuso-elevata ; apertura lata et subrotundd ; labro sim-
plicit; columella levi.

Shell globose, dark horn colour, translucent, umbilicated, longitudinally striate ;
whorls five; spire obtusely elevated ; aperture wide and round; outer lip simple;
columella smooth.

Hab. China, near Canton. W. W. Wood.
My Cabinet.
Cabinet of Mr Hyde.
Diam. -6, Length -5 of an inch.

Remarks.—I owe to the kindness of Mr Wood the specimen which
is here figured. It is remarkable for its globular form and its dark
horn-coloured epidermis. It has somewhat the aspect of a Paludina.

PALUDINA BI-MONILIFERA. Plate XIX. fig. 71.

Testé abbreviato-turritd, tenebroso-corned, apice obtusé ; anfractibus seriebus
duabus nodulorum circumdatis ; nodulis seriet inferioris anfractuum superior-
um sutura celatis ; nodulis seriei superioris majoribus, et super omnes anfrac-
tus conspicuis; suturis profundis et irregularibus ; labro sub-biangulato ; basi
subangulata.

Shell obtusely turrited, dark horn colour ; apex obtuse ; whorls furnished with two
rows of nodules ; the nodules of the lower row of the upper whorls hidden by the su-
ture, those of the upper row larger, and visible on all the whorls ; sutures deep and
irregular ; outer lip sub-biangular ; base subangular.

Hab. Alabama River. Judge Tait.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of the American Philosophical Society.
Cabinet of the Academy of Natural Sciences of Philadelphia.

AND OTHER FAMILIES. 59

Cabinet of P. H. Nicklin.
Cabinet of Baron Ferussac.
Diam. 1:1, Length 1-8 inches.

Remarks.—This superb Paludina, which far surpasses in point of
beauty any of our species yet known, I owe to the kindness of Judge
Tait. Its beautiful double tuberculated cincture at once distinguishes
it from all described species. Some specimens are furnished with
dark purple bands which beautifully decorate the interior of the shell,
and give a dark rich green colour to its fine epidermis. In the others
these are wanting, and the epidermis then has a clear and more yel-
low appearance. The sutures being formed immediately over the
lower row of tubercles, they cause its line to be very irregular; and
this row itself is hidden on the upper whorls.

SUPPLEMENT.
Read before the American Philosophical Society, March 15th, 1833,

SINCE I had the pleasure to present to this Society, nearly a year
since, a Memoir on the /Vaiades and some other families, I have had it
in my power to procure several interesting species, hitherto unnoticed
_ by naturalists. In the large collection of rare shells which I procured
in Europe while there last. year, some of these were discovered; and
most of them are, perhaps, the only specimens known, being now first
described. The observations on, and corrections of, Lamarck’s Vaiades,
it is hoped, will prove useful to the American conchologist.

VOL. V.—P 2

60 ON THE NATADES.

Unio PARALLELOPIPEDON. Plate VIII. fig. 20.

Testa oblonga, subcylindraced, transversd, valde inequilaterali, postice angu-
lata, inflatd, marginibus dorsi et baseos parallelis ; valvulis subcrassis ; natibus
prominulis, retusis ; epidermide fere nigrd ; dentibus cardinalibus obliquis, cris-
tatis ; lateralibus longis rectisque ; margarita alba et tridescente.

Shell oblong, subcylindrical, dorsal and basal margins parallel, transverse, very in-
equilateral, angular behind, inflated; valves rather thick ; beaks somewhat elevated,
retuse ; epidermis almost black ; cardinal teeth oblique, crested ; lateral teeth long and
straight ; nacre pearly white and iridescent.

Hab. River Parana, Province of Corrientes.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam. -9, Length 1-2, Breadth 2-7 inches.

Shell oblong, subcylindrical, dorsal and basal margins parallel, trans-
verse, very inequilateral, flattish on the sides, angular behind, inflated ;
substance of the shell rather thick; beaks rather elevated and placed
near the anterior margin; ligament long and thin; umbones flattened ;
umbonial slope carinate ; posterior slope elevated into a carina; epider-
mis finely wrinkled and almost black; cardinal teeth oblique and crested,
larger in the right valve; lateral teeth long and straight; anterior cica-
trices distinct; posterior cicatrices confluent; dorsal cicatrices placed
in the centre of the cavity of the beaks; cavity of the beaks shallow;
nacre pearly white and iridescent.

Remarks.—This species is from the Burrough collection, and is dis-
tinct from any I have seen. It resembles somewhat, in the outline of
the margin, the nasutus of Say. The posterior slope does not, how-
ever, decline so much, the dorsal and basal margins being nearly
parallel. In being subcylindrical it resembles the eylindricus of Say ;
it has not, however, either tubercles or arrow-headed markings. The
very dark colour of its epidermis is peculiar.*

Since the above description and the figure were made, I have seen a more perfect
specimen in the possession of Dr Burrough, which has the beaks but little eroded. In

PL. VIM Vol.5

Unie paratleloptpedon

Unto lacteolus vnie Coopertanis

a

"

———

AND OTHER FAMILIES. 61

Unio Coorerranus. Plate VIII. fig. 21.

s° ~

Testd suborbiculatd, nonnihil obliqua, inequilaterd, dimidio postico tuberculata ;
valvulis crassis; natibus prominentibus ; dentibus cardinalibus subgrandibus ;
lateralibus subbrevibus, crassis rectisque ; margarita alba et carnis colore tinctd.

Shell suborbicular, somewhat oblique, inequilateral, tuberculated on posterior half;
valves thick; beaks elevated; cardinal teeth rather Jarge; lateral teeth rather short,
thick and straight ; nacre flesh coloured and white.

Hab. River Ohio. T. G. Lea.
My Cabinet.
Cabinet of Mr Cooper.

Diam. 1-9, Length 2:8, Breadth 3-2 inches.

Shell suborbicular, somewhat oblique, inequilateral, irregularly
tuberculated on the posterior half; substance of the sheil thick ; beaks
thick and elevated; ligament rather short and thick; epidermis wrin-
kled, dark rusty brown; rays scarcely visible; cardinal tooth rather
large and widely cleft in the left valve, single and emerging from a
pit in the right valve; lateral teeth rather short, thick and straight;
anterior and posterior cicatrices both distinct; dorsal cicatrices situated
on the under part of the cardinal tooth; cavity of the beaks deep and
angulated; nacre flesh coloured and white, the white usually forming
a broad border between the palleal cicatrix and the margin.

Remarks.—This species very closely resembles, in most of its char-
acters, both the verrucosus (Barnes) and pustulosus (nobis). It differs
from the first in never being chocolate coloured. It is rarely, I believe,
entirely white like the latter. The epidermis is dark, and when rays
can be seen on it, they will be found to be pencilled, and not one broad

this I found a character not perceptible in the eroded one from which the description was
made, the beaks being furnished with radiated folds nearly similar to those of the lacteolus
and Burroughianus described herein. ‘This character seems to prevail very much in the
South American Uniones. Among the numerous species described from North America, none
yet have been observed to possess this character.

yoL. V.—Q

62 ON THE NAIADES,

interrupted one like the pustulosus. There is a great peculiarity in
the flesh or pink colour of the nacre, which is disposed to be clouded,
and to be of a stronger hue about the teeth, while the cavity of the
beak is nearly white.

I dedicate this species to my friend, William Cooper, Esq., as a slight
acknowledgement of the many favours received in the way of commu-
nications, and the loan of specimens.

Unio emarGrInATus. Plate IX. fig. 22.

Testa sub-ellipticd, ad basim emarginatd et compressa, transversissimda, valde
inequilaterd, postice sub-triangulatd; valvulis subcrassis; natibus prominulis,
apicibus undulatis ; epidermide viridi-luted ; dentibus cardinalibus parvis, obliquis,
et in valvula utrdque duplicibus ; lateralibus longis subcurvisque; margarita
alba et tiridescente.

Shell sub-elliptical, emarginate and compressed at base, very transverse, very inequi-
lateral, sub-biangular behind ; valves somewhat thick; beaks rather elevated and undu-
lated at tip; epidermis greenish yellow ; cardinal teeth small, oblique and double in
both valves ; lateral teeth long and slightly curved ; nacre pearly white and iridescent.

babi. Si:
My Cabinet.

Diam. 1, Length 1:3, Breadth 2-8 inches.

Shell subelliptical, emarginate and compressed at base, very trans-
verse, very inequilateral, sub-biangular behind, elevated along the um-
benial slope, flattened on the umbones; substance of the shell somewhat
thick ; beaks rather elevated, retuse and undulate at the tip; ligament
long and thin; epidermis finely wrinkled, greenish yellow, along the
posterior slope green; cardinal teeth small, oblique and double in both
valves; lateral teeth long and slightly curved; anterior cicatrices dis-
tinct; posterior cicatrices confluent; dorsal cicatrices situated on the
under part of the cardinal tooth; cavity of the beaks subangular and
wide; nacre pearly white and iridescent.

Remarks.—I procured two opposed valves of different individuals of
this species, which nearly match, of Mr Stutchbury, a well known and

Unio emarginatus

Untw Conradicus

ae

AND OTHER FAMILIES. 63

extensive dealer in London. He could not give me the least idea of
its native country. From its general appearance I should presume it
to come from a southern latitude, perhaps from New Holland. It is
rather peculiar in its outline, being more emarginate at base than any
species with which I am acquainted. The emargination is not, how-
ever, so great as in the Mya margaritifera (Lin.), Alasmodonta arcuata
(Barnes). It approaches most closely the Unio subtentus (Say), but
differs from it in the total absence of folds or “ribs” on the posterior
slope. In the two valves which I possess there appear to be no rays,
unless the green of the posterior slope be denominated a single broad
one. The emargination and compression of the base cause the poste-
rior part of the cavity of the shell to be effuse.

Unio Conrapicus. Plate IX. fig. 23.

Testd ellipticd, transversd, inequilaterd, parte posteriori plicatd ; valuulis tenui-
bus; natibus ad apices nitide undulatis ; dentibus cardinalibus parvis et erectis ;
lateralibus indistinctis ; margaritd antice albd, postice iridescente et in cavo fusco
purpured.

Shell elliptical, transverse, inequilateral, folded on the posterior parts ; valves thin ;
beaks finely undulated at tip ; cardinal teeth small and erect ; lateral teeth not perfectly
defined ; nacre white anteriorly, iridescent posteriorly, and brownish purple in the
cavity.

1201) Sees Professor Troost.
My Cabinet.
Cabinet of Professor Troost.

Diam 6, Length °8, Breadth 1-8 inches.

Shell elliptical, transverse, inequilateral, indistinctly folded on the
posterior parts; substance of the shell thin behind, thicker before ;
beaks slightly elevated and finely undulated at tip; ligament rather
long and thin; epidermis finely wrinkled, yellowish brown, with nu-
merous indistinct greenish rays, which on the posterior part are dis-
posed to be clouded; cardinal teeth small, erect, disposed to be lobed:
lateral teeth long, slightly curved, not perfectly defined, having but a
small cleft in the left valve; anterior cicatrices distinct; posterior cica-

64. ON THE NAIADES,

trices confluent; dorsal cicatrices in the centre of the cavity of the
beaks ; cavity of the beaks shallow and tinged with brownish purple ;
nacre white anteriorly, thinner and very iridescent posteriorly.

Remarks.—I owe to the kindness of professor Troost this little
species, and name it after an indefatigable naturalist, Mr T. A. Con-
rad. It belongs to that group which is distinguished by an imma-
ture hinge, and which I have noticed in my remarks on the U. Hil-
drethius. The U. Conradius certainly resembles that shell closely. It
is, however, less cylindrical, and has the teeth more perfect. It also
has rays and undulations which I have not observed on the other. In
outline it more closely resembles the U. iris (nobis), but differs in the
teeth and in the rays. Having but two specimens of this species to
examine, some of the characters may be found to differ in other speci-
mens. One of these is slightly emarginate at the basal margin.

Unto pivaricatus. Plate IX. fig. 24.

Testa ellipticd, transversd, subcompressd, valde inequilaterd ; valvulis tenuibus ;
natibus plicis pulchris divaricatis; dentibus cardinalibus parvis, compressis ;
lateralibus longis et subtenuibus ; margarita alba et iridescente.

Shell elliptical, transverse, rather compressed, very inequilateral ; valves thin ; beaks
with beautiful divaricating folds ; cardinal teeth small, compressed ; lateral teeth long
and rather thin ; nacre white and iridescent.

Hab. Egypt. Duke de Rivoli.
My Cabinet.

Diam. °5, Length °9, Breadth 1-4 inches.

Shell elliptical, transverse, somewhat compressed, very inequilate-
ral; substance of the shell thin; beaks covered with beautiful folds
diverging from their apex; ligament rather short and slender; epi-
dermis greenish, smooth; cardinal teeth small, compressed, double
in the right valve, and single in the left; lateral teeth long, rather
thin and nearly straight; anterior cicatrices slightly confluent ; pos-
terior cicatrices confluent; dorsal cicatrices situated in the centre of

AND OTHER FAMILIES. 65

the cavity of the beaks: cavity of the beaks shallow and subangular ;
nacre white and iridescent.

Remarks.—This beautiful little species I procured from the cabinet
of the Duke de Rivoli in Paris. It appears to me to be inedited, and
may perhaps have been considered a transverse variety of the corru-
gatus (Lam.). It ought not to be confounded with that species,
being much more transverse, and the folds of the beaks differing.
Lamarck, in his description of the corrugatus, says, “rugis angulato-
flexuosis.” The folds of the divaricatus are well marked, without an-
gles, and diverge from the point of the beaks.

Unio Corrranus. Plate IX. fig. 25.

Testa angusto-ellipticd, transversissima, valde inequilaterd, postice subangu-
lata; valvulis tenuissimis ; natibus viz prominulis ; dentibus cardinalibus tenuibus
et laminatis ; lateralibus longis, tenuibus, subrectisque; margaritd alba et irides-
cente.

Shell narrow-elliptical, very transverse, very inequilateral, subangular behind ; valves
very thin ; beaks scarcely prominent ; cardinal teeth thin and bladed ; lateral teeth long,
thin and nearly straight ; nacre pearly white and iridescent.

Hab. India. Mrs Corrie.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.

Diam. -6, Length 1, Breadth 2-1 inches.

Shell narrow elliptical, very transverse, very inequilateral, subangu-
lar behind ; dorsal line nearly straight ; substance of the shell very thin;
beaks very slightly elevated and minutely waved at the tip; ligament
long and slender; epidermis smooth, dark brown; rays none; cardinal
teeth thin, bladed, single in the /eft valve and double in the right;
lateral teeth long, thin, bladed and nearly straight; anterior cicatrices
distinct ; posterior cicatrices confluent ; dorsal cicatrices situated nearly
in the centre of the cavity of the beaks; cavity of the beaks exceed-
ingly shallow; nacre pearly white and iridescent.

YOL. ¥.—R

66 ON THE NAIADES,

Remarks.—I am indebted to an amiable and intelligent friend, Mrs
Corrie of Birmingham, England, for this new species, which comes
from Calcutta; and to her I dedicate it, as a mark of sincere friendship.
It closely resembles the U. marginalis of Lamarck, but differs from
that species in being more transverse, in the beaks being more retuse,
in the dorsal line being nearly straight, and in its not being possessed
of a light border along the margin. The cardinal teeth are remark-
ably thin, and form nearly a line with the lateral teeth.

Unio Grayanus. Plate IX. fig. 26.

Testa lanceolata, transversissimd, antice rotundata et postice acutissime angu-
lata, prope nates et partem posticam plicatd ; lateribus planulatis ; clive umboniali
subcarinato; valvulis tenuibus; natibus prope marginem anticam locatis, de-
pressis ; epidermide luteola, obsolete radiata; dentibus cardinalibus in valvuld
utrdque duplicibus et erectis; lateralibus longissimis, tenuibus, sub-erectisque ;
margarita pulchréa et iridescente.

Shell lanceolate, very transverse, rounded before and very acutely angular behind,
plicate about the beaks and posterior part of the shell, flattened on the sides ; umbonial
slope ridged ; valves thin; beaks depressed, placed near the anterior margin ; epidermis
yellowish with obsolete rays; cardinal teeth double in both valves and erect; lateral
teeth very long, thin and nearly straight ; nacre beautifully pearly and iridescent.

Hab. China.
My Cabinet.
Cabinet of Mr Hyde.
Cabinet of Mr Gray, London.

Diam. °6, Length °8, Breadth 3:3 inches.

Shell lanceolate, very transverse, very inequilateral, rounded before
and very acutely angular behind, irregularly folded in the region of
the beaks, several larger folds on the anterior slope, on the poste-
rior portion the folds are parallel being nearly perpendicular to the
basal margin, flattened on the sides; umbonial slope elevated into a
ridge, green; substance of the shell thin; beaks depressed, placed very
near to the anterior margin; ligament thin, not very long; epidermis
finely wrinkled, yellowish with obsolete rays, disposed to be greenish

=

Z ce

Crete Sowerhranus . nwo dromas

Union Burrowgqnranus . nog “Pre Reee

Irawn b Dray te

AND OTHER FAMILIES. 67

on the posterior part; cardinal teeth double in both valves, compressed
and erect; lateral teeth very long, thin and nearly straight; anterior
cicatrices distinct ; posterior cicatrices confluent; dorsal cicatrices situ-
ated in the cavity of the beaks; cavity of the beaks very small; nacre
beautifully pearly and iridescent.

Remarks.—This is perhaps the most extraordinary Unio that has
yet fallen to the lot of a naturalist to describe. When we cast our
eyes over all the species, and then rest them on this, we shall be ready
to exclaim, that nothing hereafter belonging to this genus can astonish
us. Its latitude is so great, that one at first sight can scarcely believe
it to belong to the family Naiades. Its great transverseness causes the
lateral teeth to be exceedingly long, and that character, together with
the acutely angular posterior margin, gives the shell the form of a
crane’s beak. In outline it does not approach any species I know, and
therefore there can be no comparison made. I procured it of a dealer
in London, and dedicate it to my friend, John Edward Gray, Esq. of
the British Museum, one of the most distinguished naturalists in Great
Britain, and to whose great kindness and attention while in London I
am much indebted. I know of no zoologist who has, in that country,
pursued our favourite science with more ardour or more success, and
it is only due to him, while it gives me great pleasure to render him
this tribute of respect in placing his name to one of the most inte-
resting species of the whole family.

Unio Burrovenranus. Plate X. fig. 27.

Testé subrotundd, inequilaterali, compressa, postice subangulata ; natibus obli-
que plicatis, prominulis ; valvulis subcrassis ; epidermide tenebroso-fuscd ; dentibus
cardinalibus magnis, elevatis et laminatis, lateralibus subrectis ; margarité alba
et iridescente.

Shell subrotund, inequilateral, compressed, subangular behind, with oblique folds on
the beaks ; valves rather thick ; beaks somewhat elevated and much plicate ; epidermis
dark brown ; cardinal teeth large, elevated and lamelliform ; lateral teeth nearly straight;
nacre pearly white and iridescent.

68 ON THE NAIADES,

Hab. River Parana, Province of Corrientes. Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. 1, Length 1:8, Breadth 2:4 inches.
Shell subrotund, inequilateral, compressed, subangular behind, with
large oblique folds on the beaks; substance of the shell rather thick;
beaks somewhat elevated and distinctly plicate as far as the umbones;
ligament short and thin ; epidermis smooth, dark brown with transverse
yellow marks of growth; cardinal teeth large, elevated, lamelliform
and double in both valves; lateral teeth lamelliform and nearly straight ;
anterior cicatrices and posterior cicatrices confluent; dorsal cicatrices
in the centre of the cavity of the beaks; cavity of the beaks subangular
and shallow; nacre pearly white and iridescent.

Remarks.—This is of the collection of Dr Burrough, sent by him
to the Academy of Natural Sciences of Philadelphia. ‘To this gentle-
man natural science is much indebted for his unwearied industry in
contributing to the knowledge of the Fauna—of the numerous countries
through which he has travelled, in Asia, as well as on this continent.
This species resembles most, perhaps, the Jacteolus (nobis), but differs
from it in being more round in the outline, in having longer and larger
folds on the beaks, and in being more compressed. In the beaks it
has some resemblance to the corrugatus (am.), as well also as in the
outline; but the folds being nearly parallel to each other, it differs from
the corrugatus in these, which are usually zig zag in the latter shell.
I owe to the kindness of Dr Burrough the specimen in my cabinet,
and I have great pleasure in dedicating the species to him.

Unio Sowersianus. Plate X. fig. 28.

Testa subtriangulari, inflatd, parte posticd peculiariter compressd et striatd ;
valvulis crassissimis ; natibus valde prominentibus, dentibus cardinalibus magnis ;
lateralibus crassis subrectisque ; margarita in cavo albido-purpured.

3

. AND OTHER FAMILIES. 69

Shell subtriangular, inflated, singularly compressed on the posterior part, which is
striate ; valves remarkably thick; beaks very prominent ; cardinal teeth large ; late-
ral teeth thick and nearly straight ; nacre in the cavity very light purple.

Hab. Tennessee. G. B. Sowerby.
My Cabinet.
Cabinet of Mr Sowerby.

Diam. 1:5, Length 1:7, Breadth 1-8 inches.

Shell subtriangular, inflated, singularly compressed on the posterior
part, which is filled with strie passing from the beak to the posterior
and posterior-basal margins, the anterior part being inflated and smooth ;
slightly emarginate at posterior basal margin; substance of the shell
very remarkably thick, less so on the posterior part; beaks large and
very prominent; ligament short and thick; epidermis bright brown,
smooth and shining before, striate behind ; cardinal teeth large, sulcate,
elevated and cleft in the left valve, and emerging from a pit in the
right valve; lateral teeth thick, short and nearly straight; anterior and
posterior cicatrices both distinct ; dorsal cicatrices situated on the under
part of the cardinal teeth ; cavity of the beaks shallow and subangular ;
nacre very light purple in the cavity, and white on the anterior margin.

Remarks.—To the kindness of G. B. Sowerby, Esq., one of the
most distinguished writers on conchology in England, I owe the pos-
session of this truly interesting shell, and to him I with great pleasure
dedicate it. He received it from the state of Tennessee, but from
what river I do not know. In general outline it resembles somewhat
the frigonus (nobis), bué differs from it in being more rotund, in hav-
ing the posterior part compressed and striate, and in being coloured
inside. It has a stronger resemblance to the Haysianus (nobis) than to
any other species known to me, but differs frem it in being more com-
pressed behind, in being more striate, in being much larger (to judge
from the few specimens I have seen of both), and in the difference of
the colour of the nacre, the Haysianus being dark chocolate, while the
Sowerbianus is of a very light purple, approaching to flesh colour.

VOL. Y.—S

70 ON THE NAIADES,

Unto promas. Plate X. fig. 29.

Testd subtriangulari, subobliqua, gibbd, irregulariter transversimque plicatd,
punctiunculis passim radiata; valvulis crassissimis; natibus prominentibus ;
dentibus cardinalibus latis, lateralibus crassis brevibusque; margaritd alba.

Shell subtriangular, somewhat oblique, hunch-backed, irregularly and transversely
folded, with dotted rays over the whole disk ; valves very thick; beaks elevated ; car-
dinal teeth wide ; lateral teeth short and thick ; nacre pearly white.

Hab. Harpeth River, Tennessee. Professor Conrad.
Hab. Cumberland River, near Nashville. Professor Troost.
My Cabinet.
_ Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Professor Troost.
Cabinet of P. H. Nicklin.
Diam 1°6, Length 1°8, Breadth 1-9 inches.
Shell subtriangular, somewhat oblique, hunch-backed, irregularly
and transversely folded at the separate stages of growth, furnished with
an oblique furrow before the umbonial slope, substance of the shell
very thick; beaks thick and elevated; ligament short, thick and dark
coloured; umbones furnished with a hump; epidermis yellow, with
numerous dark green dotted rays, on the anterior part furnished with
about six somewhat broad rays; cardinal tooth wide and sulcate; lateral
tooth short and thick, having a flat plate between it and the cardinal
tooth; anterior and posterior cicatrices both distinct; dorsal cicatrices
situated on the under side of the cardinal tooth; cavity of the beaks
deep and angulated; nacre pearly white, on the posterior part some-
times golden.

Remarks.—I have had for some years in my cabinet two specimens
of this beautiful and curious species, the first of which, a young one, I
owe to the kindness of the late professor Conrad. Having recently
received a complete suite from professor Troost, I have perfectly satis-
fied myself of (what I before doubted) its being distinct from the
irroratus (nobis). The manner in which the hump is formed is very
remarkable. As far as the third or fourth stage of growth the disks

AND OTHER FAMILIES. “1

are almost flat. The deposit of the nacre after this forms an angle of
nearly 45° with the surface which it has left, thus forming a hump, or
obtuse angle point, directly on the umbo. This causes the curious
result, that when the shell is from one third to three fourths grown,
it will rest, when so placed, on the portion of surface between the
point of the beak and the umbo, the basal margin remaining in the air.
In its general characters it resembles the irroratus, but may at once be
distinguished by the hump. It is devoid of tubercles, while the irro-
ratus is sometimes covered with them, particularly on the posterior
part. It differs somewhat also in the rays, the spots in those of the
dromas being larger, and generally better defined. The outline differs
in being less elongated, being disposed to be more oblique or more
transverse. In regard to the structure of the animal, am not prepared
to say that it differs from that of the irroratus.* Not having had an
opportunity to examine the animal, I can only judge by analogy, which
would, I think, induce one to conelude that the same curious pendent
oviducts would be found in both. I hope to be able to procure from
professor Troost a specimen in that period of gestation.

Unto Troostensis. Plate X. fig. 30.

Testa scalend, cuneatd, obliqua, valde inxquilaterali ; valvulis antice crassiori-
bus; natibus subterminalibus ; epidermide luteold, radiis capillaribus multis ; den-
tibus cardinalibus elevatis, cristatis ; lateralibus subrectis ; margarita alba et iri-
descente.

Shell sealeniform, wedge shaped, oblique, very inequilateral ; valves thicker ante-
riorly ; beaks nearly terminal ; epidermis yellowish, filled with numerous capillary
rays ; cardinal teeth elevated, crested ; lateral teeth nearly straight ; nacre pearly white
and iridescent.

Hab. Cumberland River. Professor Troost.
My Cabinet.
Cabinet of Professor Troost.

* See vol. ili. p. 271.

72 ON THE NATADES,

Diam. °8, Length °1, Breadth 1:9 inches.

Shell scaleniform, cuneated, oblique, very inequilateral, angular be-
hind; substance of the shell thick before, thinner behind ; beaks ele-
vated and rounded; epidermis very finely wrinkled, shining, yellowish
brown with numerous green flexuous capillary rays over the whole
disk ; ligament rather short and thick ; cardinal teeth elevated, crenate,
deeply cleft in the left valve, and emerging from a pit in the right
valve; lateral teeth long and nearly straight; anterior cicatrices distinct ;
posterior cicatrices nearly distinct; dorsal cicatrices situated in the
centre of the cavity of the beaks; cavity of the beaks very shallow;
nacre beautifully pearly white and iridescent.

temarks.—Ii owe to the great kindness of professor Troost the ex-
amination of his select specimens, which he most obligingly sent to
me for that purpose. Among them were two specimens of this rare
and beautiful species, unsurpassed by any other in the delicacy and
exquisite beauty of its rays. In general form it approaches the scale-
nius (Rafinesque), but differs from it in the form of the rays altogether.
It differs also in colour and in having the beaks less retuse. In dedi-
cating this rare and beautiful species to my friend, professor Troost, I
do him but an act of simple justice. His constant efforts in the pro-
motion of the physical sciences are known and acknowledged, and his
investigation in this branch of conchology will do much to illustrate
its history in his adopted state.

Unto perpix. Plate XI. fig. 31.

Testa ellipticd, postice subangulatd, subequilaterali, inflata, transversd ; valvu-
lis subcrassis ; epidermide luteold, radiis irregulariter interruptis ; dentibus car-
dinalibus elevatis ; lateralibus prope eorum fines majoribus ; margarita alba et
tridescente.

Shell elliptical, subangular behind, nearly equilateral, inflated, transverse ; valves
rather thick ; epidermis yellowish with irregularly interrupted rays; cardinal teeth
elevated ; lateral teeth larger near their termination ; nacre pearly white and iri-
descent.

2

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AND OTHER FAMILIES. 73

Hab. Harpeth River, Tennessee. Professor Troost.
My Cabinet.
Cabinet of Professor Troost, Nashville.
Diam. 1-4, Length 1:9, Breadth 3-1 inches.
Shell elliptical, subangular behind, nearly equilateral, inflated, trans-
verse ; substance of the shell rather thick; beaks slightly elevated and
without undulations at tip; ligament short and thick; epidermis yel-
lowish with irregularly interrupted rays over the whole disk; cardinal
teeth elevated, double in the left valve and single in the right; lateral
teeth enlarged and disposed to be bladed at the termination; anterior
cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices situ-
ated along the base of the cardinal tooth and under the plate between
the cardinal and lateral teeth; cavity of the beaks wide and obtusely
angulate; nacre pearly white, extending only far enough to leave a
broad horn coloured border.

Remarks.—This species was among the shells sent to me by professor
Troost. To judge from the few specimens I have seen, I should sup-
pose it varied much from age as well as locality. One of my speci-
mens is old and very large, scarcely presenting a ray. In this state it
closely resembles the U. obovatus (nobis), but is rather more trans-
verse. The younger and more perfect specimens approach more
closely to the U. crassus (Say), but are more inflated, and differ in the
rays, Which are broken into irregular spots, not entirely dissimilar to
the plumage of the partridge. It has some resemblance to the U. pic-
tus herein described, but is not compressed like that species, and differs
in the rays. In some specimens the teeth are disposed to be pinkish.

Unio Picrus. Plate XI. fig. 32.

Testd ellipticd, compressa, inequilaterali ; valvulis subtenuibus ; natibus com-
pressis et ad apices undulatis ; epidermide luted, radiis tenebroso-viridibus inter-
ruptis ; dentibus cardinalibus parvis ; lateralibus longis et subcurvis ; margarita
albéd et iridescente.

VOL. Vo—T

74 ON THE NAIADES,

Shell elliptical, compressed, inequilateral ; valves rather thin ; beaks compressed and
undulated at tip ; epidermis yellow with interrupted dark green rays; cardinal teeth
small; lateral teeth long and slightly curved ; nacre pearly white and iridescent.

Hab. Harpeth River, Tennessee. Professor Troost.
My Cabinet.
Cabinet of Professor Troost.

Diam. :8, Length 1-6, Breadth 2°6 inches.

Shell elliptical, compressed, inequilateral; substance of the shell
rather thin, thicker before; beaks compressed and finely undulated at
the tip; ligament short and rather thick; epidermis fine yellow with
numerous oblique interrupted rays, which are strongly pencilled at the
commencement of each stage of growth; cardinal teeth very small and
erect; lateral teeth long and slightly curved, in the left valve enlarged
near the termination; anterior cicatrices distinct; posterior cicatrices
confluent; dorsal cicatrices in the centre of the cavity of the beaks, and
deeply impressed ; cavity of the beaks very shallow and rounded ; nacre
pearly white and iridescent.

Remarks.—This species, so beautiful and so peculiar in its painted
exterior, [ owe to the kindness of professor Troost. ‘The fine specimen
figured belongs to the museum of that gentleman in Nashville, and I
am indebted to him for the loan of it to insert it here. It belongs to
a group, the peculiar character of which seems to be in the singular
interruption of the rays, which are obsolete, except at the commence-
ment of each stage of growth, where they are strongly pencilled with
green. The U. planulatus (nobis), U. patulus (nobis) and U. perdix
(herein described) belong to this group. The U. pictus has some re-
semblance to the U. cariosus (Say), but differs in being more com-
pressed, and in having rays over the whole disk. It perhaps more
closely resembles the younger specimens of U. crassus (Say). It dif-
fers, however, in being thinner, smaller, and in the character of the
rays.

AND OTHER FAMILIES. 75

SympnynoTa piscomEA. Plate XI. fig. 33.

Testa subrhombed, compressa, transversd, inequilaterali, valvulis tenuissimis,
postice connatis; natibus paulum undulatis, compressis; dentibus in valvuld
utraque lineam simplicem facientibus ; margarita alba et iridescente.

Shell subrhomboidal, compressed, transverse, inequilateral ; valves very thin, con-
nate behind ; beaks slightly undulated, compressed ; teeth in both valves forming a
simple line ; nacre white and iridescent.

Hab.....* G. B. Sowerby.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of W. Hyde.

Diam. 1:2, Length 2:4, Breadth 3-9 inches.

Shell subrhomboidal, compressed, transverse, inequilateral, finely
wrinkled; substance of the shell very thin; posterior slope elevated
into a moderately high wing, which is connate; beaks very slightly
undulated, compressed ; ligament linear; epidermis dark brown; teeth
in both valves forming a simple, continuous, fine curve line; anterior
and posterior cicatrices both distinct; dorsal cicatrices situated in the
centre of the cavity of the beaks; cavity of the beaks almost none:
nacre white and iridescent.

Remarks.—I owe to the kindness of G. B. Sowerby, Esq. the spe-
cimen here described. He procured it of “a dealer from Holland,”
and its habitat is unknown. It has the characters of an eastern shell.
and probably came from Java. In the outline of the margin it resem-
bles the Symphynota magnifica (described in this memoir), but differs
from it in being compressed and in the possession of teeth. In the
teeth it has a stronger resemblance to the S. bialata (nobis) than to
any other species. It is, however, less defined, and the curve is less
regular, the posterior portion being nearly straight. In the elevation
of the wing it differs totally. Our present shell forms an interesting

* Dr Burrough has recently obtained it in the rivers of China, and to him I owe the fine
specimen figured.

76 ON THE NAIADES,

link in the gradual change of the characters of the teeth. It ap-
proaches that division of the Maiades which do not possess teeth, more
closely than any species which has come under my notice.

ANODONTA LATO-MARGINATA. Plate XII. fig. 34.

Testa obovatd, transversa, inequilaterali ; intus margine latd et corned; sinu
longo et in partem internam disci vergenie ; valvulis crassis ; epidermide rubido-
fusca; margarita alba et tridescente.

Shell obovate, transverse, inequilateral, interior with a broad horn coloured border ;

sinus long, and pointed towards the interior of the disk ; valves thick ; epidermis red-
dish brown; nacre pearly white and iridescent.

Hab. River Parana, South America. Dr Burrough.

My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. 1°5, Length 2°5, Breadth 3-5 inches.

Shell obovate, transverse, inequilateral, inflated, interior with a broad
horn coloured border; sinus long, and pointed to the interior of the
disk ; substance of the shell thick ; beaks somewhat elevated ; ligament
long and thick; epidermis reddish brown, finely wrinkled, and some-
times obscurely rayed; anterior cicatrices distinct; posterior cicatrices
confluent; palleal cicatrices almost imperceptible; dorsal cicatrices ap-
parently none; cavity of the beaks shallow and subangular; nacre
pearly white and iridescent, extending only to the broad horn coloured
border.

Remarks.—In the collection of Dr Burrough there are several spe-
cimens of this species, some of which are young and more rotund than
that figured here. It presents several characters unusual in the species
of this genus, so far as our knowledge extends. ‘The horn coloured
border is even broader than that of the fenebricosa herein described,
and the apparent absence of the dorsal cicatrices I have never noticed
before in any species of the family. The sinus of this species is very
remarkable, as well as that of the /enebricosa. It does not, however,

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AND OTHER FAMILIES. Md

like that species, curve towards the cavity of the beaks; it stretches in
a point towards the centre of the cavity of the disk. In general out-
line it resembles the dn. Patagonia (Lam.), but differs in being less
rotund, less inflated, and in the nacre being white.

ANODONTA BLAINVILLIANA. Plate XII. fig. 35.

Testa ovata, inflatd, valde inequilaterali, antice angulatd, postice latissima,
ad marginem anteriorem hianti; cicatrice marginali lata et postice valde incurvé ;
valvulis subcrassis; natibus prominulis; margine dorsali recta; margarita sal-
monis colore tinctda.

Shell ovate, inflated, very inequilateral, angular before, very wide posteriorly, gaping
at the anterior and posterior margins; palleal cicatrix broad and much incurved poste-
riorly ; valves rather thick; beaks somewhat prominent; dorsal line straight; nacre
salmon and pearly.

Hab. Chili? .
My Cabinet.

Diam. 1:3, Length 1:9, Breadth 3 inches.

Shell ovate, inflated, very inequilateral, angular before, very wide
posteriorly, the greatest length being perpendicular from the extreme
posterior end of the ligament to the basal margin, gaping much at the
anterior margin, and rather less at the posterior margin; substance of
the shell somewhat thick; beaks rather prominent; dorsal line straight,
having a slight elevation under the beak like an incipient tooth; ante-
rior cicatrices complicated but distinet; posterior cicatrices wide and
confluent; dorsal cicatrices numerous and stretched in a line across the
cavity of the beaks; marginal cicatrix wide, deep and much incurved
near to the posterior cicatrix; nacre salmon, beautifully pearly and iri-
descent.

Remarks.—I accidentally met with this interesting shell at a shop
in Havre last October, a few days previously to my embarkation. The
two valves belong to different individuals, but they very nearly match.
They have both been slightly mutilated by an attempt to beautify

VOL. Y.—U

78 ON THE NAIADES,

them, the epidermis having been almost completely removed. What
remains indicates it to be greenish, and is sufficient to warrant its being
represented in the figure with a perfect epidermis—the ligament has
also been destroyed. I was informed by the dealer that it came from
Chili; such authority cannot, however, be entirely relied on. The
cicatrices of this interesting species are very remarkable, particularly
that of the mantle near the margin; the palleal impression is wide,
deeply impressed, and in the posterior part of the shell deflected towards
the centre of the cavity, somewhat similar to the excavation of the
palleal cicatrix of the genera Galathea and Mactra. The character of
this cicatrix is different from that of any species of the family Natades
I have seen, and this peculiarity induces me to believe that the animal,
when found, may prove to be different from that of the nodonta.
Should this be the case, it will belong of course to a new genus, for
which I propose the name of Columba. It somewhat resembles the
‘An. exotica (Lam.). It is, however, narrower before and broader be-
hind than that shell. It gapes anteriorly and posteriorly more than
any of the Maiades with which I am acquainted. It is perhaps most
nearly allied to the nodon crassus (Swainson), but differs in the dor-
sal line being straight, the nacre being pearly salmon, as well also in
the peculiar character of the palleal cicatrix.

ANODONTA TENEBRICOSA. Plate XII. fig. 36.

Tesla ellipticd, transversd, inequilaterd, intus margine laté et corned; sinu
incurvo ; valvulis crassis ; epidermide tenebroso fuscd ; margaritd alba subceruled
purpura nubild, iridescente.

Shell elliptical, transverse, inequilateral, interior with a broad horn coloured border;
sinus incurved ; valves thick ; epidermis dark brown; nacre pearly white, clouded with
bluish purple, iridescent.

Hab. River Parana, South America. Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadelphia.

AND OTHER FAMILIES. 79

Diam. 1:5, Length 1-9, Breadth 3-3 inches.

Shell elliptical, transverse, inequilateral, with a broad horn coloured
border, emarginate at base; sinus incurved; substance of the shell thick ;
beaks scarcely prominent; ligament long and thick; epidermis dark
olive brown, wrinkled, obscurely rayed on the posterior slope ; anterior
cicatrices distinct; posterior cicatrices confluent; palleal cicatrix large
and partially tinted with bluish purple; dorsal cicatrix situated in the
centre of the cavity of the beaks; cavity of the beaks very shallow:
nacre pearly white clouded with bluish purple, extending only to the
broad horn coloured border, iridescent.

Remarks.—This curious species is from the collection sent to the
Academy of Natural Sciences by Dr Burrough. It differs distinctly
from any species known to me. ‘The horn coloured broad border, and
the absence of nacreous matter on this part is very remarkable, as is
also the close approximation to a perfect ellipsis, the posterior and an-
terior margins being nearly of the same curve. The clouded bluish
purple colour I have never seen in the nacre of any other species. The
sinus is so peculiar in the two specimens examined, that I would
impress it as important in the character of this species. In the An.
exotica (Lam.), a South American species, the sinus is generally of
the form of an equilateral triangle, the inferior angle being sharp and
well defined. In the present species the sinus is still more remark-
able, curving in towards the cavity of the beak and terminating with
quite an acute angle. The line of the opening of the two specimens
is curved and not a plane, as usual with the aiades ; and the right
beak and margin anterior to it, overwrap in a small degree the left
beak and valve. In the old specimen this extension of the margin
passes the other more than an eighth of an inch—consequently the
shell might almost be said to be inequivalve. In its general characters
this species most resembles the s¢nwosa of Lamarck.

80 ON THE NAIADES,

AwnoponTa Mortonrana. Plate XIII. fig. 37.

Testa subelliptica, postice sub-biangulata, transversd, valde inequilaterali ; val-
vulis crassis ; epidermide perfuscd ; clivo umboniali sulcato ; margarita argented

et iridescent.

Shell subelliptical, sub-biangular behind, transverse, very inequilateral ; valves
thick ; epidermis intensely brown ; umbonial slope furrowed ; nacre silvery and iri-
‘descent. ;

Hab. River Parana, South America. Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of Dr Burrough.

Diam. 1:2, Length 1:6, Breadth 3 inches.

Shell subelliptical, sub-biangulate behind; transverse, very inequi-
lateral, somewhat inflated, furrowed from the beak to the posterior
margin along the umbonial slope; substance of the shell thick; beaks
retuse and scarcely prominent; ligament long and narrow; epidermis
intensely brown and finely wrinkled ; anterior cicatrices distinct ; pos-
terior cicatrices confluent; dorsal cicatrices apparently none; cavity of
the beaks subangular and shallow; nacre silvery white and iridescent.

Remarks.—A single specimen of this species, which is distinct from
any described nodonta I have seen, was sent to the Academy by Dr
Burrough. It is remarkably thick, silvery and iridescent, and has an
exceedingly dark epidermis. It most resembles, perhaps, the elon-
gaius of Swainson. It is less transverse than that shell, rounded only
anteriorly; it differs in not having “a strong flesh coloured tinge,” and
is by no means so bright a brown as his beautiful figure.

Named after S. G. Morton, M.D., corresponding secretary of the
Academy of Natural Sciences of Philade}phia.

Taney 5

Rae Nata, = a s :
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AND OTHER FAMILIES. 81

MELANIA AcULEUs. Plate XIX. fig. 72.

Testa acuto-elevata, levissimd, tenebroso-corned ; apice acutissimo ; anfractibus
circiter duodecim, subconvexis ; labro expasso.

Shell acutely elevated, very smooth, dark horn colour; apex very acute ; whorls
about twelve, somewhat convex ; labrum spread out.

Hab. Java?
My Cabinet.
Diam -6, Length 2 inches.

Remarks.—I purchased this, with some other of the shells described
in this memoir, from the collection brought from Java by Mr Shilla-
ber. It is remarkable for its attenuated form and tapering spire. It
is more than usually spread out at the base. The substance of the
shell is thin and bluish white. The last whorl is much enlarged.
The aperture occupies about one-third of the length of the shell.

LyMN#A IMPERIALIS. Plate XIX. fig. 73.

Testd ovato-ventricosd, pellucida, tenuissimd, albido-corned, subcoronata ; apice
obtuso ; anfractibus quaternis, inflatis, ultimo maximo ; aperturd magna, ovate ;
labro valde extenso.

Shell ovato-ventricose, diaphanous, very thin, light horn colour, subeoronate ; apex
obtuse ; whorls four, inflated, the last very large; aperture large, ovate ; outer lip
much extended,

Hab. South America?
My Cabinet.
Diam. -9, Length 1:4 inches.

Remarks.—I accidentally met with this rare and interesting shell
at a dealer’s in Paris. I saw no other specimen in any of the great
collections in Europe. The person from whom I obtained it informed
me it came from South America. It is more inflated than any spe-

VOL. ¥.—Y

82 ON THE NAIADES,

~

cies with which I am acquainted; but what eminently distinguishes
it is the subcoronate apex which, as far as we yet know, is peculiar to
this species. The body whorl nearly envelopes the superior ones.
When examined by the microscope, transverse striz are observed to
cause numerous minute depressions on its surface.

MELANOPSIS PRINCEPS. Plate XIX. fig. 74.

Testé acuto-elevatd, levi, rufo-fuscd, obsolete multimaculatad; inferiori anfractu
carinato, dimidio basali transversim striato ; apice acuto ; anfractibus plus minus
guatuordecim, planis ; apertura quintd parte testx.

Shell acutely elevated, smooth, transversely striate on the lower half of the body
whorl, which is carinate, reddish brown, with numerous indistinct spots ; apex acute ;
whorls about fourteen, flat aperture one-fifth the length of the shell.

Hab. Cape of Good Hope.
My Cabinet.
Diam. °6, Length 2-1 inches.

Remarks.—This is the most remarkable species of the genus which
I have examined. It differs from any described species in its great
elevation, in the flatness of its whorls, in its being covered with indis-
tinct spots, and in the absence of a large callus on the superior part of
the inner lip, as well also as in the great number of its whorls. The
spots are peculiar in being chain-like, alternately darker and lighter.
The operculum is horny, like that of the genus Melania.

MELANoPsiIs MACULATA. Plate XIX. fig. 75.

Testa fusiformi, tenebroso-olivaced, intus fasciatd ; epidermide maculata ; an-
Sractibus quaternis ; basi sublruncatd ; columella sine callo superno.

Shell fusiform, dark olive, banded on the inside, and spotted in the epidermis ;
whorls four ; base but slightly truncate; columella not thickened above.

—e

AND OTHER FAMILIES. 83

Hab. Peru. Lieutenant Humphreys.
My Cabinet.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. °3, Length -5 inches.

Remarks.—The genus Melanopsis, a few years since, presented, to our
knowledge, only twospecies. These were described by Lamarck. The
rapid advancement of our science has recently brought to light many
new ones. I have eight species in my own cabinet, and in this memoir
I add two species to the ten now known. These two are peculiarly
and beautifully spotted in the epidermis. The two specimens brought
by lieutenant Humphreys have each four transverse purple bands on
the inside, and the dark olive epidermis is filled with very distinct in-
tensely dark brown quadrate spots. This species, and the princeps
herein described, form a division in the genus Melanopsis of Lamarck
which genus should be altered, leaving out the character of the callus
on the upper part of the columella. Neither of these has that char-
acter, but, notwithstanding, should not be removed to a new genus, as
it is, independent of that, a perfectly natural one.

AURICULA FUscCAGULA. Plate XIX. fig. 76.

Testa fusiformi, albidd, pellucida ; suturis impressis et albo-lineatis ; labro late
refleco; guld fusca et dentibus novenis munitd.

Shell fusiform, whitish, diaphanous ; sutures impressed and presenting a white line ;
outer lip widely reflected ; throat dark brown and furnished with nine teeth.

Hab. Brazil.
My Cabinet.
Cabinet of P. H. Nicklin.
Diam. °4, Length 1-1 inches.

Remarks.—This is a very remarkable and interesting species. In
its general form and aperture it resembles a Clausilia. Like some
species of that genus its mouth is studded with teeth. Of the nine,

84 ON THE NATADES,

seven are on the outer lip—the last of these and the first on the colum-
ella are the largest. The deep brown of the throat is visible through
the shell. In some specimens there is a finely mottled appearance
over the lower whorls of the shell. The white line along the suture is
placed on the upper part of the whorl. The outline of the shell is
remarkably fusiform.

CycLosToMA sTRIATA. Plate XIX. fig. 77.

Testa depressd, planulatd, multistriatd, alba, pellucida, latissime umbilicata ;
anfractibus quatlernis; apice acuminato, rufo; labro acuto; operculo corneo
tenuique.

Shell depressed, flattened, much striate, white, translucent, very widely umbilicate ;
whorls four ; apex red and pointed ; lip sharp; operculum thin and horny.

Hab. Peru. Lieutenant Humpbreys.

Cabinet of the Academy of Natural Sciences of Philadelphia.
Diam. °9, Length -5 of an inch.

Remarks,—This shell was brought by lieutenant Humphreys from
South America, and presented, with many other fine specimens, to the
Academy. It resembles the C. Jamaicensis (Fer.); but is much larger,
and has finer strie. The rotundity of the mouth is slightly modified
by the junction of the superior part with the columella.

AcHATINA VANUXEMENSIS. Plate XIX. fig. 78.

Testa fusiformi, tenut, pellucida, longitudinuliter et transversim striatd, luted,
in anfractum infernum obsolete albo-maculatd ; suturis granulatis ; canali baseos
curvo.

Shell fusiform, thin, pellucid, longitudinally and transversely striate, ochre coloured,
with indistinct white spots on the body whorl ; sutures granulate ; channel curved at
the base.

AND OTHER FAMILIES. 85

Hab. Mexico. Professor Vanuxem.
My Cabinet.
Cabinet of Professor Vanuxem.
Cabinet of the Academy of Natural Sciences of Philadelphia.
Cabinet of P. H. Nicklin.
Diam. 1-2, Length 2-5 inches.

Remarks.—Among the shells brought from Mexico by professor
Vanuxem, was this fine Achatina, which belongs to Lamarck’s second
division of this genus. It very closely resembles the Buccinum striatum
(Chem.), Polyphemus glans* (Say), Glandina (Say). It differs from
it in having crenulated sutures, and in having fine transverse lines, as
well as longitudinal striz. The indistinct opake white spots, which
are more frequent on the front of the body whorl, are, I believe, pecu-
liar to this species. It is larger by one-third than any individual of
the striata which I have seen.

In concluding these descriptions and observations, I will take ad-
vantage of the opportunity to express my thanks to those gentlemen
who have kindly assisted me with new shells and rendered other
friendly offices. Among these I have been particularly obliged by
Philip H. Nicklin, Esq., William Cooper, Esq. and professor Troost.
To the Academy of Natural Sciences of Philadelphia an acknowledge-
ment is due, for the liberal and unhesitating vote which it passed, to
permit me to describe for our Transactions the new species in their
splendid and highly useful collection.

I will take this opportunity also to correct the habitat of the Unio
brevidens (Vol. IV. page 75), which professor Troost thinks has not been
found in the Ohio, but only in the Cumberland. The specimen which
Mr Cooper kindly gave to me to be described, came, I believe, originally
from professor Troost. ‘The specimen figured was not more than half
grown. ‘The older individuals usually have an arched ridge along the

* Cochlicopa rosea (Fer.). It should now be called Achatina striata, unless the generic
name be changed, the propriety of which I doubt.

VOL. V.—W

86 ON THE NAIADES,

umbonial slope near to the margin, the edges of each growth being there
dentate. In some specimens this is so strongly marked as to resemble
athick cord. The 4rceformis, professor 'T. doubts being in Tennessee
river. He found it only in the Cumberland. He was, I believe, the
first person who sent this species to New York and this city. Some
fine old specimens, recently received from that gentleman, exhibit a
diameter of a most extraordinary nature, as well also an almost perfect
flatness of the posterior slope. My oldest specimen, when placed on
a plane, will rest both on the base and on that slope. The specimen
figured by me, was not more than two-thirds grown, and was then the
best specimen I had seen, and I supposed it to be an adult.

OBSERVATIONS ON LAMARCK’S NAIADES.

Havine had the opportunity while in Paris recently, to inspect most
of the cabinets to which Lamarck refers in his description of the
Naiades, I seized the opportunity to examine the individual specimens
from which he made his descriptions; and having made notes on the
spot, I fee] great confidence as to the facts,and trust that my judgment
as to the decisions on his species will be found to be correct.

In pointing out the errors of this great zoologist, we must not be
astonished at their number, nor should the slightest shadow fall upon
his merited and exalted reputation. We should rather think of the
means within his power, the poverty of the materials with which he
worked, and above all, the unfortunate ophthalmia which afflicted his
declining years, and which he deplores in the advertisement of the
sixth volume of his Hist. Nat. des Animaux sans Vertébres.

Unio sinuata. This is a true species, but Klein is entitled to the
name which he gave first to it, viz. crassissima.* It has been consi-
dered by the conchologists of this country (and I certainly was of the

* See Transactions of the Linnean Society of Bourdeaux, Vol. II. p. 42.

AND OTHER FAMILIES. 87

same opinion) to be the Mya margarififera of Linneus. It has all
the characters of this species, with the exception of the addition of the
thick lateral tooth, which our author does not describe, but could
scarcely have failed to have observed. Being possessed of this tooth,
it is of course a true Unio. Pfeiffer describes an old margaritifera
under the name of sinuata. He says “ dente cardinali valido, subcon-
ico, laterali nullo.” In the north of Europe, (for the sinwata exists
only in the south) he had not, perhaps, like ourselves, until recently, an
opportunity of examining the true stnwata of Lamarck.

Unio elongata. This is the true Mya margaritifera of Linneus
and other authors. The asmodonta arcuata of Barnes is its ana-
logue in this country. It inhabits the north of Europe, lake Ladoga,
Norway, &c.

Unio crassidens. The specimen quoted from Lamarck’s own col-
lection, which is now in the possession of the Duke de Rivoli, is the
euneatus of Barnes. Var. a is the trapezoides (nobis), a shell very
different in its general characters, being always folded. Crassidens
therefore has precedence of euneatus.

Unio Peruviana. ‘his is the plicatus of Le Sueur, now so well
known in all our collections. Valenciennes says, Dombey’s shell re-
mains in the museum, and that Lamarck described a North American
shell in error. The figure referred to by Lamarck, in the Ency.
Methodique. is certainly the well known plicatus of our western waters.

Unio purpurata. Wamarck supposed the specimens he examined
to have come from Africa. I examined the specimen cited, in the
Duke de Rivoli’s collection, as well, also, one in that of Baron de
Ferussac. ‘These specimens have been polished, and have, most pro-
bably, been in the cabinet of Paris for twenty or thirty years; for, few
Uniones were admitted into the cabinet, at that time, without the loss
of their superficial protection. It is the ater (nobis), and, most pro-
bably, was taken from the neighbourhood of New Orleans, while in
possession of the French. The specimen described and figured in one
of my former memoirs, came from Port Gibson, below Natchez; and I
subsequently received some from the vicinity of New Orleans and from
Claiborne, Alabama. J therefore, willingly yield the name to Lamarck.*

* In the “* American Conchology,” No. V., Mr Say re-describes and re-figures the Unio

88 ON THE NATADES,

Unio ligimentina. 'The specimen in the Garden of Plants is the
U. crassus of Say.

Unio obliqua, in the same collection is the U. undatus of Barnes.

Unio retusa. This is the U. torsus (Rafinesque). The locality given
is Nova Scotia; the correctness of which I doubt much. It is, as yet,
known to exist only in our western waters.

Unio rarisuleata. 'The specimen in the Garden of Plants is the
complanatus (Soland.), purpureus of Say.

Unio coarctata. ‘he specimen in the collection of the Duke de
Rivoli is the complanatus (Soland.). "The observation of Lamarck, that
“it is the analogue of our U. margaritifera,’ (he ought to have said
elongata, for he does not use the name of margarilifera) must be an
error. The American shell, described by Barnes as Alasmodonta ar-
cuata, is the unquestionable analogue of the true Mya margaritifera
(Linn.), and a very different shell, not having a lateral tooth, and
belonging to Schumacker’s genus Margaritana (Say’s lasmodonta).

Unio purpurascens. This is also a complanatus, in the museum of
the Garden of Plants.

Unio radiata. The specimen at the Garden of Plants is the true
radiatus. ‘The Unio ochraceus (Say), given as a synonyme, is a very
distinct species.

Unio brevialis. The specimen at the Garden of Plants resembles so
closely the U. littoralis, that I am induced to believe it never came
from the Isle of France, and that it is of European origin. That in
Baron de Ferussac’s cabinet is certainly an old Jiftoralis. The shell
figured by Crouch, under the name brevialis, is entirely distinct.

Unio rhombula. 'The specimen now in the cabinet of the Duke de
Rivoli* is a young and bad specimen of the complanatus, and certainly
from the United States, and not Senegal. Var. 6, in the cabinet of
Valenciennes, | did not see. :

ater, under the name of U. lugubris, alleging that the name afer is ‘* preoccupied by Nilsson
for a very distinct species.”’ Mr S. does not seem to be aware, that Nilsson’s ater is only a
variety of U. Batava, of Maton and Racket; and, therefore, could not affect my claim. We
must both yield to the prior claim of Lamarck.

* T ought to say that the Duke keeps the cabinet of Lamarck intact, as much as possible, and,
therefore, the shells quoted may be relied on as being the same as described by Lamarck.

AND OTHER FAMILIES. 89

Unio carinifera is also the complanatus, which inhabits so large a
space of our country east and west of the Alleghany mountains.

Unio Georgina is also from the mine complanatus.

Unio clava. This is the scalenia of Rafinesque: modioliformis of
Say.

Unio recta is Barnes’s prelongus. Lamarck has precedence.

Unio naviformis. This is the cylindricus of Say, who has prece-
dence.

Unio glabrata. This is the complanatus. 'The specimen in the
Duke de Rivoli’s cabinet is most likely from our eastern waters.

Unio nasuta. The specimen from which this description was made,
is nowin the museum of the Garden of Plants. It is a young gibbosus
of Barnes. It is not the same with Say’s nasufus, as Lamarck sus-
pected it to be. As Lamarck described the shell before Barnes, he
has a claim for the species; but having used a name pre-occupied by
another shell, he loses it. I therefore would continue Mr Barnes’s
name gibbosus.

Unio ovata is the ovatus of Say. Var. b, I was not enabled to see
—from the description I presume it to be a variety of occidens (nobis).

Unio rotundata. The specimen shown to me by Baron de Ferussac,
whose cabinet is cited for one of the two specimens seen by Lamarck,
is a small suborbiculata (Lam.), a large specimen of which the baron
had the goodness to give me, and I have reason to believe it to be the
individual cited by Lamarck. It is the subglobosus (nobis), and the
glebulus of Say.

Unio littoralis. This interesting species inhabits most parts of Eu-
rope. It has been brought also from the Tigris by some of the French
scientific expeditions, and I owe to the kindness of the administration
of the Garden of Plants a fine specimen from Bagdad. ‘The specimens
from this locality are less transverse, and Lamarck considered the dif-
ference sufficient to found a species, semirugata, by which name they
are labelled in that institution. After examining carefully suites from
Europe and Asia with Baron de Ferussac, he accorded with me in
opinion, that there was not sufficient difference to warrant their sepa-
ration.

VOL. ¥.—xX

90 ON THE NAIADES,

After examining numerous specimens in Europe of the liftoralis, I
have strong doubts if the shell described by me in a former memoir,
under the name of incurvus, be not a peculiar variety of it. — It cer-
tainly has a marked similarity to a fine transverse specimen of Jilforalis.
The specimen from which my description was made, was sent to me
as a “non descript from Gibraltar,’ by Mrs Mawe. I had not at that
time seen very fine specimens of the /ifforalis, and it did not strike me

_ that there was a similarity to such as I had. While in London, that
excellent conchologist, Mr G. B. Sowerby, showed me a specimen
precisely similar to mine, and which I think he informed me was from
the collection of the veteran Humphreys. In one valve was marked
in ink “Brazil;” in the other the name of the person who is supposed
to have brought it from that country.

Unio semirugata. 'The specimen which I examined in the Duke
de Rivoli’s cabinet, is the one mentioned as being in Lamarck’s own
cabinet. It is a young Jifforalis, with rather more undulations than
usual.

Unio nana. I saw this species only in the collection of Baron de
Ferussac. All the specimens were old and depauperated, and their
similarity to liltoralis so great, as to induce me to believe that when
better individuals are procured, they will easily be referred to that
species.

Unio delodonfa. The specimen cited, and which I examined in the
cabinet of the Duke de Rivoli, I suspect to be the /acteolus (nobis).
It has the beaks eroded, and therefore does not present the peculiar
character of radiating folds at the point of the beaks, which is conse-
quently omitted in Lamarck’s description.

Unio sulcidens. In the Duke de Rivoli’s collection—it is a com-
pressed complanatus (Soland.), from the Connecticut River, where
this species is more disposed to assume that character than in any
river in the United States with which I am acquainted.

Unio rostrata. This is one of the numerous species made from the
pictorum of authors. It is merely an elongated variety of that species
in all the cabinets where I have seen it in Europe.

Unio Batava. This is a distinct species from pictorum. Baron de
Ferussac thinks that Maton and Racket are entitled to the species.

AND OTHER FAMILIES. 9]

Lamarck cites Schroeter first. I have not an opportunity to examine
Schroeter’s work.

Unio nodulosa. This is a young individual of the ovata of Dono-
van, and no doubt the specimen cited never was out of Europe. The
ovata is emphatically an European shell, and has served, like the pie-
torum, to which it has some resemblance, to make numerous species.
Lamarck’s habitat (lake Champlain) is certainly an error.

Unio varicosa. 'The specimen described by Lamarck is still in his
original cabinet. It is a young and bad specimen of the #/asmodonta
marginata (Say). From the description I formerly supposed it to be
Alas. undulata (Say).

Unio granosa. 'The only specimen of this beautiful and distinct
species I saw in Europe, is in the Garden of Plants. It is unique in
the possession of disks completely covered with minute granular ele-
vations.

Unio depressa. The specimen in the Duke de Rivoli’s collection is
marked “from Peru,” and is a very different species from one which
I procured in Paris, marked by Lesson as depressa from New Holland.
Lamarck’s description is so extremely vague, that it almost equally
well applies to both. The shell from Peru, of which I have several
specimens, is more transverse than that from New Holland, which I
presume should be considered the true depressa.

Unio Virginiana. ‘This isa bad specimen of radiatus, in the Duke
de Rivoli’s collection.

Unio luteola. From the description and locality, I formerly sup-
posed this to be Say’s cariosus. On examining the specimen at the
Garden of Plants, cited by Lamarck, I found it to be a true siliquoi-
deus of Barnes, which sometimes approaches the cariosus. 'There
must be an error in the locality given by Lamarck, as this species does
not inhabit the waters east of the Alleghany mountains. Lamarck’s
name has precedence to that of Mr Barnes.

Unio angusta. This isa distinct and interesting species. Its habi-
tat is unknown, and the only specimen I have seen is in the collection
at the Garden of Plants.

Unio manca. I examined the original specimen in the cabinet of

92 ON THE NAIADES,

Baron de Ferussac, which Lamarck described, and I convinced the
Baron that it was only a pictorum.

Unio cariosa. 'The two specimens described are both in the cabi-
net of the Duke de Rivoli. The first is a bad specimen of Say’s cario-
sus. 'The other (Var. 2) is a bad specimen of the asmodonta mar-
ginata (Say). One of the habitats, Lake Erie, is an error; it is found
only in our waters east of the Alleghany mountains.

Unio spuria. 'This species is mentioned by Lamarck as being in the
museum of the Garden of Plants. I did not see it there, nor do I
know it to be in any other collection.

Unio australis. ‘The same remarks apply to this species.

Unio anodontina. I examined the individual described under this
name in the collection of the Duke de Rivoli. It proved to be a spe-
cimen of U. marginalis, which species is yet known to inhabit only the
fresh waters of India. Lamarck says it comes from Virginia, which is
certainly an error.

Unio suborbiculata. ‘This is only a rotundafa, as mentioned before
in my observations on that species.

Hyria avicularis. This is the Mya syrmatophora of Gronovius,
Gmel., Dill., &c.: avicularis should therefore be abandoned. Lamarck
is not certain of the habitat of his specimen, but believes it to be from
Brazil. I have seen in Paris a specimen brought by Spix from that
country.*

Hyria corrugata is remarkable for the folds on the umbones, and is

a very distinct species.—They are both in my cabinet.

Anodonta cygnea. The well known Mytilus cygneus of Linneus
and others. Of the various forms of this there have been created per-
haps a dozen different species.

Amodonta anatina resembles very closely the eygnea, but is: most
probably a distinct species. Poiret asserts that this species is 6vipa-

* This traveller brought also the Castalia ambigua, which, Lamarck says, seems to be flu-
viatile, but which he nevertheless separates from the Naiades, to which it naturally belongs,
and not to the family Zrigoniana. Both the shells are figured in Spix’s beautiful work, but
described with too little attention to previous writers.

AND OTHER FAMILIES. 93

rous, while the cygnea is viviparous. Should this prove true, they
must of course be considered distinct.

Anodonta sulcata. I saw in the Duke de Rivoli’s cabinet the spe-
cimen described by Lamarck. It is a variety of the 2. cygnea, and I
presume is from Europe. The cygnea has no analogue in the United
States, with which f£ am acquainted.

Anodonta fragilis. Baron de Ferussac gave me a specimen of this
species, brought by Monsieur Lapylaie from Newfoundland. When
I first saw it in Paris, I recognized it instantly to be similar to speci-
mens I had found in lake Skaneateles, nearly six years since, but which
I had not yet published.

Anodonta rubens. 'This interesting species is perhaps the most pon-
derous of the genus. It inhabits the Nile as well as the Senegal. My
specimen, from the latter river, is heavier and more inflated than those
which I have from the Nile. Deshayes places it in the genus Jridina,
asserting that the animal differs from the .2nodonta, and is similar to
that of the Jridina.

Anodonta crispata. 'This is a distinct and beautiful species, peculiar
for its transverse furrows. I owe to the kindness of Baron de Ferussac
the possession of this rare shell, the habitat of which is Cayenne.
Lamarck says, “ dans les riviéres des regions australes ?”

‘nodonta uniopsis is a distinct species, and probably from New
Holland.

Anodonta Pennsylvanica. examined the specimen described by
Lamarck. It is in the cabinet of the Duke de Rivoli, and is the same
with the wndulata of Say, rugosus of Swainson.

Anodonta intermedia is a variety of analina. 'The intermedia of
Pfeiffer is a variety of cygnea.

Anodonta trapezialis. The specimen described by Lamarck is in
the Garden of Plants. It is the giganteus of Spix, who figures it in
his beautiful work. Its habitat is Brazil. Lamarck says, “des eaux
douces étrangéres a celles de Europe?” It is less transverse, and has
more volume than the following, which it closely resembles.

nodonta exotica. I examined specimens of this species in the
cabinets of the Duke de Rivoli, Baron de Ferussac and the Garden of
Plants. Lamarck’s habitat says, “les riviéres de ’Inde?” I believe

VOL. V.—Y

94 ON THE NATADES,

it comes only from the more southern rivers of South America. My
specimens, and those I saw in Europe, came from the river La Plata.
It has a peculiar character, which Lamarck does not notice, in the
deposit of epidermal matter at different stages of growth, with the nacre
extending in waved lines, generally from one great cicatrix to the other,
forming curves parallel with the palleal cicatrix.

Anodonta glauca is a distinct species, inhabiting Mexico, and figured
in a recent number of Humboldt’s great work.

‘Anodonta sinuosa. I saw the specimen described, in Baron de
Ferussac’s cabinet. It is very distinct, and very peculiar in the sinuous
dorsal line. This species is in my cabinet.

Anodonta Patagonica. This isalso a distinct and very rare species.
The possession of a specimen I owe to the kindness of Mr G. B.
Sowerby.

Tridina exotica. 'To Baron de Ferussac I owe the possession of this
species. It appears to differ from the Milotica in being tuberculated
along the dorsal line, which is one of Lamarck’s generic characters.
The Milotica, which I received from the African traveller Monsieur
Cailliaud, has no crenulations along the dorsal line, but I have seen
specimens on which a few could be observed. The Clappertoni of
Denman is a young Milotica.

AND OTHER FAMILIES. 95

SECOND SUPPLEMENT.

Read before the American Philosophical Society, February 7th, 1834.

Unio Suerarpranus. Plate XIII. fig. 38.

Testa sublanceolata, transversissima, valde inequilaterali, antice rotundatd,
postice obtuso-angulatd, inferne emarginatd, ad latera planulatd ; clivo umboniali
elevato; valvulis subcrassis; natibus parvis, prope marginem anteriorem posilis ;
epidermide tenebroso-fuscd, obsolete radiata ; dente cardinali obliquo, in valvula
dextra unico, in sinistrad duplici ; dente laterali longissimo rectoque ; margaritd
purpurea et iridescente.

Shell sublanceolate, very transverse, very inequilateral, rounded before, obtusely
angular behind, emarginate at base, flattened on the sides; umbonial slope elevated ;
valves somewhat thick ; beaks small and placed near the anterior margin ; epidermis
dark brown with obsolete rays; cardinal teeth oblique, single in the right and double
in the left valve ; lateral teeth very long and straight ; nacre purple and iridescent.

Hab. Hopeton, near Darien, Georgia. Professor Shepard.
My Cabinet.
Cabinet of Professor Shepard.

Diam. 1, Length 1-4, Breadth 5 inches.

Shell sublanceolate, very transverse, very inequilateral, rounded be-
fore, obtusely angular behind, emarginate at base, flattened over the
umbones and sides ; umbonial slope forming an oblique ridge ; substance
of the shell rather thick; beaks small and placed near to the anterior
margin; ligament thin and long; epidermis dark brown, almost black,
with obsolete rays on the more perfect individuals; cardinal teeth erect,
single in the right valve and double in the left; lateral teeth very long
and straight; anterior cicatrices distinct ; posterior cicatrices confluent ;
dorsal cicatrices in the centre of the cavity of the beaks: cavity of the
beaks very shallow; cavity of the shell deep under the umbonial slope :
nacre beautifully purple and iridescent.

96 ON THE NAIADES,

Remarks.—This remarkable species, in its great transverseness and
outline, has some resemblance to U. Grayanus (nobis). It is much
more transverse than any species heretofore discovered from this coun-
try. The purple of the interior is like that of the complanatus (Soland.).
In one specimen there is a muscular impression near the centre of the
cavity of the shell, similar to that of the U. trapezoides (nobis). In
another specimen there are obsolete marks of an impression. The third
has none that can be distinguished.

T am indebted to the great kindness of professor Shepard of New
Haven for this interesting and curious species, and it is with pleasure
I dedicate it to him.

Unio Futyus. Plate XIII. fig. 39.

Testd angusto-ellipticd, inequilaterali, transversd, posticé subangulata ; clivo
umboniali rotundato ; valvulis tenuiculis ; natibus prominulis ; epidermide luted ;
dente cardinali obliquo, laéerali subcurvo ; margaritd salmonis colore tinctd.

Shell narrow-elliptical, inequilateral, transverse, subangular behind ; umbonial slope
rounded ; valves rather thin ; beaks slightly elevated ; epidermis yellow ; cardinal teeth
oblique ; lateral teeth somewhat curved ; nacre salmon.

Hab... .. , South Carolina. Dr Blanding.
My Cabinet.
Cabinet of Dr Blanding.

Diam. °6, Length °9, Breadth 1-6 inches.

Shell narrow-elliptical, inequilateral, transverse, slightly inflated ;
umbonial slope rounded; substance of the shell rather thin; beaks
slightly elevated, placed towards the anterior margin; ligament thin
and rather short; epidermis yellow and yellowish brown; cardinal teeth
oblique, short, disposed to be lobed, single in the right and double in
the left valve ; lateral teeth slightly curved, rather long; anterior cica-
trices distinct ; posterior cicatrices confluent; dorsal cicatrices placed in
the centre of the cavity of the beaks; cavity of the beaks very shallow ;
cavity of the shell somewhat deep; nacre salmon.

AND OTHER FAMILIES. 97

Remarks.—This species has, perhaps, most resemblance in its exte-
rior to the marginalis (Lamarck), which comes from the great rivers
of India. In the interior, however, it differs much. Our shell is of a
very dark salmon colour. It is also a thicker shell, and the teeth are
much thicker. In the colour of the epidermis it somewhat resembles
the lanceolatus (nobis).

Unio moprouirormis. Plate XIII. fig. 40.

Testa ovatd, transversd, inxequilaterali, inflatd, antice angustd, postice lata ;
valvulis tenuissimis ; natibus minutis et fere terminalibus ; dentibus cardinalibus
parvis, compressis, lateralibus longis curvisque; margarild subpurpured, valde
iridescenti. ‘

Shell ovate, transverse, very inequilateral, inflated, narrow before and broad behind ;
valves very thin; beaks small, nearly terminal ; cardinal teeth small, compressed ;
lateral teeth long and curved ; nacre slightly purple, very iridescent.

Hab. Santee Canal, South Carolina. Professor Ravenel.
My Cabinet.
Cabinet of Professor Ravenel.
Cabinet of P. H. Nicklin.

Diam. 1:1, Length 1°5, Breadth 2-7 inches.

Shell reversely ovate, transverse, very inequilateral, inflated, narrow
before and broad behind, emarginate at basal margin; substance of the
shell very thin, diaphanous; beaks small, nearly terminal, slightly un-
dulated ; ligament rather long and thin; epidermis brown, shining ; rays
indistinct; cardinal teeth small, compressed, disposed to be double in
the left and single in the right valve ; lateral teeth long, curved and ele-
vated in their direction; anterior cicatrices distinct; posterior cicatrices
confluent; dorsal cicatrices small, situated in the cavity of the beaks;
cavity of the shell deep; cavity of the beaks shallow; nacre slightly
purple, very iridescent.

Remarks.—The spreading out of the posterior portion of the shell,
and the narrowness of the anterior portion, is very striking in this spe-
VOL. V.—Z

98 ON THE NAIADES,

cies. 1 know of no other species which has its lateral teeth so much
elevated, following, as they do, the widened margin of the valve. The
cardinal teeth are generally double in the left valve, but not always.
They will always be found to be compressed in both valves, and gene-
rally more elevated in the right. The nacre is so very thin as to be
diaphanous, and the play of iridescent colours is very beautiful. As
the individual advances in age the marks of growth form large wrin-
kles, and it then becomes more cylindrical.

Unio Kirrianpranus. Plate XIV. fig. 41.

Testa subrotundd, compressa ; valvulis crassis ; natibus subprominentibus ; epi-
dermide circa nates luted, juxta marginem fuscd ; radiis interruptis ; dentibus
cardinalibus subcrassis, lateralibus subcurvis brevibusque ; margarita alba et iri-
descente.

Shell rather round, compressed ; valves thick ; beaks somewhat elevated ; epidermis
yellowish about the beaks, brown towards the margin ; rays interrupted ; cardinal teeth
rather thick ; lateral teeth short and slightly curved ; nacre pearly white and iridescent.

Hab. Mahoning, Ohio. J. P. Kirtland, M.D.
My Cabinet.
Cabinet of P. H. Nicklin.
Diam. 1, Length 2, Breadth 2-3 inches.
Shell rather round, compressed; substance of the shell thick, some-
what thinner behind; beaks rather elevated ; ligament rather short and
thick; epidermis wrinkled, dark brown, smooth and yellowish in the
region of the beaks; interrupted rays pass from the beaks and are very
visible over the umbones, but are lost in the wrinkles before they reach
the margin; cardinal teeth rather thick; lateral teeth short, thick and
slightly curved; posterior and anterior cicatrices both distinct; dorsal
cicatrices situated on the under side of the cardinal teeth; cavity of
the shell flat and shallow; cavity of the beaks rather deep and angu-
lated ; nacre pearly white and iridescent.

Remarks.—I owe this new species to the kindness of Dr Kirtland of

Vneo Paranensts

Unio Lirtlaridinnas , Trio Nashyvillzanes.

AND OTHER FAMILIES. 99

Poland, Ohio. It is very nearly allied to the swbrofundus (nobis), and
when I first received a few specimens, I doubted if it was more than
a variety of that species. Subsequently receiving from the same natu-
ralist more and better specimens, I was satisfied that it was specifically
different. Specimens of the true swbrotundus having accompanied
these, it could not be, of course, a variety occasioned, as is sometimes
the case, by mere locality. It differs from the subrotundus in being
much flatter, in having smaller beaks, and in being of a darker brown—
the beaks are less yellow—the rays, interrupted like that shell, tend
generally nearer to the margin. In older specimens than the one
figured, the posterior part becomes protruded, which gives an oblique-
ness to the shell.

Unto Paranensis. Plate XIV. fig. 42.

Testa subrotundatd, inxquiluterali, compressa; valvulis subcrassis ; natibus
plicatis retusis ; dentibus cardinalibus recurvis, in valvuld utrdque duplicibus ;
lateralibus sublongis curvisque ; margarita alba et iridescente.

Shell subrotund, inequilateral, compressed ; valves somewhat thick; beaks folded,
retuse ; cardinal teeth recurved, double in both valves; lateral teeth rather long and
curved ; nacre pearly white and iridescent.

Hab. River Parana. Dr Burrough.
Cabinet of Dr Burrough.

Diam. 1:3, Length 3, Breadth 3:5 inches.

Sheil subrotund, disposed to be pentagonal, inequilateral, compressed
towards the margin, emarginate on the posterior dorsal margin; um-
bonial slope flattened; substance of the shell somewhat thick; beaks
rather elevated, longitudinally folded, retuse ; ligament rather long and
thin; epidermis wrinkled, shining, greenish on the beaks and brown
towards the margin, furnished with very obscure curved rays, which
sweep from the beak towards the anterior part ; cardinal teeth recurved,
compressed, double in both valves; lateral teeth lamellar, rather long
and curved; anterior cicatrices confluent; posterior cicatrices confluent ;

100 ON THE NATADES,

dorsal cicatrices in the centre of the cavity of the beaks; palleal im-
pression small and distant from the margin; cavity of the shell very
shallow ; cavity of the beaks smal], subangular; nacre pearly white and
iridescent.

Remarks.—I am indebted to the kindness of Dr Burrough for the
advantage of examining and describing this interesting species. It was
procured by him, during his late voyage round the world, at Buenos
Ayres, having been brought from the river Parana. It is remarkable
for its outline, its expanded basal margin and folded beaks.

Unio Nasuviuutanus. Plate XIV. fig. 43.

Testa ellipticd, transversd, inequilaterali ; valvulis subcrassis; natibus promi-
nulis et minute undulatis ; dentibus cardinalibus laminatis et in valvuld utraque
duplicibus, lateralibus subrectis ; margarita alba.

Shell elliptical, transverse, inequilateral ; valves somewhat thick ; beaks slightly ele-
vated and minutely undulated ; cardinal teeth lamelliform and double in both valves ;
lateral teeth nearly straight ; nacre pearly white.

Hab. Cumberland River. Professor Troost.
Ohio, at Louisville. Dr Fitch.
My Cabinet.
Cabinet of Professor Troost.

Diam. °9, Length 1-4, Breadth 2-5 inches.

Shell elliptical, sometimes truncate behind, transverse, inequilateral ;
substance of the shell somewhat thick; beaks slightly elevated and
minutely undulated at the tip; ligament rather short and straight;
epidermis dark brown, obscurely rayed; cardinal teeth lamelliform,
disposed to be crenulate, double in both valves; lateral teeth nearly
straight, the inferior section in the left valve being enlarged towards the
posterior end ; anterior cicatrices distinct ; posterior cicatrices confluent ;
dorsal cicatrices in the centre of the cavity of the beaks; cavity of the
beaks angular, rather shallow; nacre beautifully pearly white, disposed
in many individuals to be pinkish on the posterior part of the shell.

FLUC:

LAMAGLG LAM
ANIL

AND OTHER FAMILIES. 101

Remarks.—This species has most resemblance in its general charac-
ters to the parvus (Barnes). It is, however, a larger shell, and in the
undulations of the beaks it is very different. Like the parvus, the sili-
quoideus, the cariosus and crassus, it is sometimes very much truncated
behind. In this state it might be mistaken for a different species, did
not, as in the abovementioned species, the other characters strictly iden-
tify it.

Unio Buanpineranus. Plate XV. fig. 44.

Testa subtrapezoided, transversd, inxquilaterali, subinflata; valvulis tenuibus ;
natibus prominulis; dentibus cardinalibus compressis; lateralibus longis cur-
wisque; margaritd purpured.

Shell subtrapezoidal, transverse, inequilateral, somewhat inflated ; valves thin; beaks
somewhat prominent; cardinal teeth compressed ; lateral teeth long and curved ; nacre

purple.

Hab. St John’s river, ? Florida. Dr Blanding.
My Cabinet.
Cabinet of Dr Blanding.

Diam. °9, Length 1-5, Breadth 2-3 inches.

Shell subtrapezoidal, transverse, very inequilateral, somewhat in-
flated; substance of the shell thin: beaks somewhat prominent.
placed near to the anterior margin; ligament rather long and narrow;
epidermis fuscous, wrinkled: cardinal teeth compressed, double in the
left valve and single in the right; lateral teeth long, curved and some-
what lamellar; anterior cicatrices distinct; posterior cicatrices conflu-
ent; dorsal cicatrices placed in the centre of the cavity of the beaks;
cavity of the shell rather deep: cavity of the beaks wide and shallow:
nacre dull purple.

Remarks.—I owe to the kindness of Dr Blanding the specimens of
this species which are in my cabinet. They were procured by this
naturalist while in St Augustine, from an Indian whom he had directed

to collect for him, and it is presumed they came from St John’s river
VOL. V.—2 A

102 ON THE NAIADES,

or some of its tributaries. This species has somewhat the characters
of the obesus (nobis), and the complanatus (Solander). It is not so
much inflated as the former, and is more so than the latter. My oldest
specimen is subemarginate on the basal margin. In all those procured
by Dr Blanding, the beaks were much eroded.

Unio caMEtus. Plate XV. fig. 45.

Testa subtriangulari, inequilaterali, complanatd per umbones a natibus usque
ad marginem inferiorem ; valvulis crassis ; radiis sparsis capillaribusque ; dente
cardinal parvo, laterali magno, crasso, curvato ; margarita albd.

Shell subtriangular, inequilateral, flattened over the umbones from the beaks to the
basal margin; valves thick; rays scattered and capillary ; cardinal teeth small; lateral
teeth large, thick and curved; nacre white.

Hab. Ohio river. T. G. Lea.
My Cabinet.
Diam. 1-4, Length 2:3, Breadth 3-4 inches.
Shell subtriangular, inequilateral, angular behind, flattened over the
umbones from the beaks to the basal margin; substance of the shell
thick; ligament thick; epidermis yellow brown, with capillary rays;
cardinal teeth small; lateral teeth very large, thick and curved; ante-
rior and posterior cicatrices both distinct; dorsal cicatrices situated on
the inferior part of the cardinal teeth; cavity of the shell shallow,
welted ; cavity of the beaks very shallow.

Remarks.—This species seems to possess partly the characters of
the gibbosus (Barnes), and partly those of the planulatus (nobis). It
may be distinguished from them by its high dorsal margin, its very
remarkably thick lateral tooth and its capillary rays.

AND OTHER FAMILIES. 103

Unio Grirriraranus. Plate XV. fig. 46.

Testi elliptica, expansa, transversd, inequilaterali, lateribus subplanulatis ;
clivo umboniali rotundato ; valvulis subcrassis ; natibus parvis ; epidermide luteolé
viridi-radiatd ; dente cardinali parvo et lobis instructo ; laterali longo, curvo et ad
lerminum posteriorem aucto; margaritd purpured, alba, vel salmonis colore tincta.

Shell elliptical, spread out, transverse, inequilateral, somewhat flattened on the sides ;
umbonial slope rounded ; valves somewhat thick ; beaks small; epidermis yellowish,
with green rays ; cardinal teeth small, lobed ; lateral teeth long, curved and enlarged at
posterior end ; nacre purple, salmon or white.

Hab. South Carolina. Professor Ravenel.
My Cabinet.
Cabinet of Professor Ravenel, Charleston, South Carolina.

Diam. -6, Length 1-2, Breadth 2-2 inches.

Shell elliptical, spread out, transverse, inequilateral ; somewhat flat-
tened on the sides, rounded on the umbonial slope; substance of the
shell somewhat thick; beaks small, scarcely elevated; ligament some-
what long and narrow; epidermis yellowish, with green diverging rays ;
cardinal teeth small, lobed, disposed to be double in both valves; lateral
teeth long, curved and enlarged at the posterior end ; anterior cicatrices
distinct ; posterior cicatrices confluent; dorsal cicatrices situated across
the cavity of the beaks; cavity of the beaks rather shallow; cavity of
the shell shallow; nacre purple, salmon or white.

Remarks.—Although this shell is very like the complanatus (Soland.),
I have thought it sufficiently distinct to separate it. It is more rounded -
before, and more spread out, forming a more perfect ellipsis. In the
nacre it is very much the same. I name it after my friend R. E.
Griffith, M.D.

Unio conrertus. Plate XVI. fig. 47.

Testa trapezoided, transversd, inequilaterali, inflata ; valvulis subcrassis ; nati-
bus prominulis et transversim rugatis ; dentibus cardinalibus compressis, et in

104 ON THE NAIADES,

valuulé utraque duplicibus ; lateralibus longis curvisque ; margarita purpurea,
aut salmonis colore tinctéd.

Shell trapezoidal, transverse, inequilateral, inflated ; valves rather thick; beaks
slightly elevated and transversely wrinkled ; cardinal teeth compressed and double in
both valves ; lateral teeth long and curved ; nacre purple or salmon.

Hab. Santee Canal, South Carolina. Professor Ravenel.
My Cabinet.
Cabinet of Professor Ravenel.
Diam. 1°1, Length 1-3, Breadth 2-4 inches.
Shell trapezoidal, transverse, inequilateral, inflated ; substance of the
shell rather thick ; beaks slightly elevated, incurved, transversely wrin-
kled; umbones very much swollen; ligament rather short and thin ;
epidermis dark brown, shining; cardinal teeth very much compressed ;
lateral teeth long and slightly curved ; anterior cicatrices distinct; pos-
terior cicatrices confluent; dorsal cicatrices on the superior part of the
cavity of the beaks; cavity of the shell very deep; cavity of the beaks
full and rounded; nacre purple or salmon.

Remarks.—The confertus, in its general characters, resembles the
complanatus (Solander). It is, however, much more inflated, and dif-
fers in having teeth more compressed. The specimens in my cabinet
I owe to the kindness of professor Ravenel. These are all without
rays. In young specimens they may exist.

SympHynoTa BenepicTensis. Plate XVI. fig. 48.

Testd trapezio simili, inequilaterd, transversa, subcompressd, margine dorsali
subrecta ; valvulis pertenuibus; natibus subprominentibus, apicibus granulatis ;
cicatricibus vie cernendis ; margarita ceruleo-alba et iridescente.

Shell trapezoidal, inequilateral, transverse, rather compressed, nearly straight on the

dorsal margin; valves very thin; beaks somewhat prominent, and granulate at tip ;
cicatrices scarcely perceptible ; nacre bluish white and iridescent.

Hab. Lake Champlain.

Beene rasan ee Symphynota Benz LLA CALS

Anodonta Burro

Unzo cornferltis

©

.
a
+
.

AND OTHER FAMILIES. 105

My Cabinet.
Cabinet of Professor Benedict, Burlington, Vermont.

Diam. 1:4, Length 2-2, Breadth 3-6 inches.

Shell trapezoidal, inequilateral, transverse, rather compressed, nearly
straight on the dorsal margin; substance of the shell very thin; epi-
dermis shining, yellowish olive, with rather strong lines of growth;
beaks somewhat prominent and granulate at tip; cicatrices scarcely
perceptible ; cavity of the beaks shallow; cavity of the disk rather shal-
low; nacre bluish white and iridescent.

Remarks.—On my way to Quebec, in the summer of 1829, I spent
a few minutes on the shore of lake Champlain, nearly opposite to fort
Ticonderoga, waiting for the steamboat. These minutes were im-
proved in the search of the shells near the edge of the water. Among
others hastily seized, was a single individual of the present species,
which, though an alive specimen, was much decorticated. Unwilling
to describe it asa new species, without better individuals for examina-
tion, I have endeavoured in vain to procure them until the present
time. I owe to the kindness of professor Benedict a suite of different
ages which verify my previous impression, and to him I dedicate the
species. In outline (except the wings) it resembles the Symphynota
bi-alata (nobis). It is not, however, so large or so thick a shell, and
has neither tooth nor undulations.

AnoponTaA Burrovcurana. Plate XVI. fig. 49.

Testa ovatd, valde inxquilaterali, subinflald ; valvulis tenuibus ; natibus pro-
minulis ; lined dorsali curvd ; margarita purpured.

Shell ovate, very inequilateral, slightly inflated ; valves thin ; beaks slightly elevated;
dorsal line curved ; nacre purple.

Hab. Island of Luconia, near Manilla. Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.

VOL. V.—2 B

106 ON THE NAIADES,

Diam. °8, Length 1:3, Breadth 2-1 inches.

Shell reversely ovate, very inequilateral, slightly inflated, rather
straight on the basal margin and elevated on the posterior dorsal mar-
gin; substance of the shell thin; beaks slightly elevated ; ligament long
and narrow; epidermis dark brown and rather smooth; anterior and
posterior cicatrices confluent; dorsal cicatrices situated in the cavity of
the beaks; cavity of the shell wide and rather deep: cavity of the
beaks very shallow; nacre purple.

Remarks.—To the kindness of Dr Burrough I am indebted for the
privilege of describing this species. Jt is with pleasure I take the op-
portunity of placing his name upon it. It was procured by him near
the city of Manilla. It resembles, in outline and colour, the Unio
cuprinus (nobis), but has no trace of teeth. It is most remarkable
perhaps for its deep colour.

Marecarirana* Ravyeneviana. Plate XVII. fig. 50.

Testa subcylindraced, valde transversd et inequilaterali, inflatd ; valvulis tenut-
bus; natibus exiguis ; dentibus cardinalibus parvis, subcompressis; margarita
ceeruleo-albd.

Shell subcylindrical, very transverse, inequilateral, inflated ; valves thin; beaks
small; cardinal teeth small, rather compressed ; nacre bluish white.

Hab. French Broad and Swananoe rivers, North Carolina.
My Cabinet.
Cabinet of Dr Ravenel.

Diam. °9, Length 1-1, Breadth 2-2 inches.

Shell subcylindrical, very transverse, inequilateral, inflated, disposed
to be compressed near the basal margin, where it is often emarginate ;
substance of the shell thin; beaks small; ligament rather short; epi-
dermis brown, with rays on the posterior part; umbonial slope large,
rounded ; cardinal teeth consisting in each valve of a smal! compressed

* See note at page 429, Vol. III.

aa

PL .XVII Vol.J.

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AND OTHER FAMILIES. 107

lobe; anterior cicatrices confluent; posterior cicatrices confluent; dorsal
cicatrices placed under the cardinal teeth; cavity of the shell deep:
cavity of the beaks shallow; nacre bluish white.

Remarks.—This species most resembles the A/asmodonta marginata
(Say), but may be distinguished by its more cylindrical form, and its
want of undulations on the posterior slope. It differs also in the round-
ness of the umbonial slope, and in the rays. In the marginata the
rays are more interrupted and scattered, being sometimes quite spotted.

Cyrena RoTuNDATA. Plate XVII. fig. 51.

Testd rotundatd, sublenticulari, subequilaterali, transversim rugatd ; clivo pos-
t | ’ oO S|
teriori rugoso ; valvulis crassis; natibus parvis, acutis, contiguis ; dentibus car-
dinalibus subbifidis, lateralibus longis, minute serratis, rectisque ; margarita alba
Ps fo} ? ? > po}
et purpured.

Shell round, sublenticular, nearly equilateral, transversely wrinkled, rugose on the
posterior slope ; valves thick; beaks small, pointed, touching ; cardinal teeth disposed
to be bifid ; lateral teeth long, straight and minutely serrulate ; nacre white and pinkish.

Hab. .
My Cabinet.

Diam. 15, Length 2:9, Breadth 3-3 inches.

Shell round, sublenticular, nearly equilateral, transversely and rather
minutely wrinkled, rugose on the posterior slope; substance of the
shell thick; beaks small, pointed, touching; ligament very short and
thick; epidermis yellowish brown before and dark brown behind ;
anterior slope furnished with a lanceolate mark formed by two curved
yellow lines, which pass from the beaks to the anterior margin; pos-
terior slope rugose, furnished with obsolete oblique folds; cardinal teeth
disposed to be bifid; lateral teeth long, straight and very minutely ser-
rulate; cicatrices scarcely perceptible ; cavity of the shell rather shallow;
cavity of the beaks subangular; nacre white and pinkish.

Remarks.—This beautiful and fine large species was sent to me

108 ON THE NAIADES,

some years since by a dealer in Paris. It perhaps most resembles the
Zeylanica (Lamarck). It differs, however, in being more compressed,
more rotund, in having longer lateral teeth, and in these being serru-
late. ‘The nacre is rather thinner, and is coloured. On comparison
it will be observed that the anterior tooth of the Zeylanica is merely
a tubercle, while that of rofundata is long and lamellar. The nacre
is disposed to be pinkish on the posterior part.

Cyrena JAyensis. Plate XVII. fig. 52.

Testa subrotunda, subequilaterali, antice rugosd; valvulis crassis; natibus par-
vis, elevatis; dentibus cardinalibus bifidis, lateralibus longis, minute serratis,
rectisque; margarita purpurea.

Shell subrotund, nearly equilateral, transversely wrinkled on the anterior part ;
valves rather thick ; beaks small, elevated ; cardinal teeth bifid; lateral teeth long,
nearly straight, and minutely serrulate ; nacre purple.

Hab. Batavia? J.C. Jay, M.D.
My Cabinet.
Cabinet of Dr Jay.

Diam. 1:1, Length 2-2, Breadth 2-3 inches.

Shell subrotund, nearly equilateral, furnished with transverse rather
large wrinkles on the anterior part; substance of the shell rather thick ;
beaks small, elevated, retuse ; ligament very short and thick; epidermis
dark brown, shining; cardinal teeth bifid, long, nearly straight and
minutely serrulate ; cicatrices scarcely perceptible; cavity of the shell
shallow ; cavity of the beaks subangular; nacre dark purple, sometimes
whitish.

Remarks.—tt is to the kindness of Dr Jay I am indebted for the
specimen figured. That of his cabinet is rather more oblique than
this. The Jayensis has some resemblance to the rofundata, described
herein, but differs in having rather large wrinkles on the anterior part,
in having more elevated beaks, and in the dark purple colour of the
nacre.

PL .XVUL Vol.5

Aphrodite caolumba

Cyrena Weadiana .

new by Sirayton

AND OTHER FAMILIES. 109

Cyrena TurcipA. Plate XVIII. fig. 53.

Testa trigond, inflata, parte antica turgidd, rugosa, inequilaterd, transversim
rugatd ; valvulis crassis ; natibus elevatis, recurvis ; dentibus cardinalibus sub-bi-
jidis, dente anteriore laterali brevi et elevato, posteriore longo et laminato ; mar-
garita albd.

Shell triangular, inflated, swollen on the anterior part, rugose, inequilateral, trans-
versely wrinkled ; valves thick ; beaks elevated, recurved ; cardinal teeth disposed to
be bifid ; anterior lateral tooth short and elevated ; posterior lateral tooth long and Jam-
ellar ; nacre white.

Hab... .. , India. Rev. William Carey.
My Cabinet.

Diam. 1-2, Length 1-7, Breadth 2-1 inches.

Shell triangular, inflated, swollen on the anterior part, rugose, in-
equilateral, transversely wrinkled ; substance of the shell thick ; beaks
elevated, recurved; ligament rather long and narrow; epidermis yel-
lowish brown, darker towards the margin; cardinal teeth disposed to
be bifid; anterior lateral tooth short and elevated, somewhat conical;
posterior lateral tooth long and lamellar ; cicatrices scarcely perceptible ;
cavity of the shell deep and rounded; cavity of the beaks angular;
nacre white.

Remarks.—To the kindness of Dr Carey of Calcutta I owe several
specimens of this species. In the teeth it resembles the C. Zeylanica
(Lamarck), and the C. papua (Lesson). It differs trom both in being
more triangular, more inflated, as well as in being a smaller species.
In the enlargement of the anterior part, which seems to be turgid or
swollen, it differs from any Cyrera with which I am acquainted.
Being without serrulate teeth, it belongs to Lamarck’s second divi-
sion—* dents latérales entiéres.

VOL. VY.—2 ©

110 ON THE NAIADES,

Cyrena Wooprana. Plate XVIII. fig. 55.

Testa subtrigond, subinflatd, micante, subequilaterali, transversim rugatd ; val-
vulis crassis; natibus magnis et rotundatis ; dentibus cardinalibus sub-bifidis,
lateralibus longis, serratis, rectisque; margarita alba.

Shell subtriangular, somewhat inflated, shining, nearly equilateral, transversely wrin-
kled ; valves thick ; beaks large and rounded ; cardinal teeth disposed to be bifid ; late-
ral teeth long, straight, serrulate ; nacre white.

Hab. Canton. W. W. Wood.
My Cabinet.

Diam. 1:4, Length 2-4, Breadth 2-9 inches.

Shell subtriangular, obtusely angular behind, somewhat inflated,
shining, nearly equilateral, transversely and rather largely wrinkled ;
substance of the shell thick; beaks large, rounded, not very approxi-
mate; ligament rather short and thick; epidermis blackish brown,
polished, except on posterior slope; wrinkles larger near to the margin ;
cardinal teeth disposed to be bifid ; lateral teeth long, straight, serrulate ;

cicatrices scarcely perceptible; cavity of the shell deep; cavity of the
beaks angular; nacre white.

Remarks.—In the intenseness of colour of the epidermis, and its high
polish, this species differs from any I am acquainted with. It is more
inflated and less rotund than the rofwndata herein described. Its
lateral teeth are longer and not so minutely serrulate. In its triangular
form it resembles the C. papua (Lesson). The nacre has not the
clear white usual in this genus. In this specimen, below the palleal
impression, it is yellowish white.

Mr Wood, to whose great kindness I owe this fine and interesting
species, informed me he procured it from a boat on the river below
Canton, it having been fished up by accident, when the fishermen
were engaged in catching other shell fish. Owing the possession of it
to him, I with great pleasure dedicate it to him.

AND OTHER FAMILIES. P11

GENUS APHRODITE (nobis).

Testé xquivalri, subtrigond, inequilaterali ; dente cardinali subnullo ; dentibus
lateralibus binis, sublongis; ligamento externo.

Shell equivalve, subtriangular, inequilateral ; hinge with a very imperfect or no car-
dinal tooth ; lateral teeth two, rather long ; ligament external.

Remarks.—The genus /phrodite is proposed for a single species
which I am unable to place with any established genus. I suspect it
to be an estuary shell, and should it proye so, its proper place will be
after the genus Cyrena. ‘The lateral teeth are placed somewhat like
those in that genus, but the epidermis and substance of the shell differ
entirely, being more like the genus Mactra.

A. cotumBa. Plate XVIII. fig. 54.

Testd subcompressd, longitudinaliter et obsolete striata, transversim et minute
rugaté, colore columbe tinctd, super umbones subrufis maculis ungulatis munitd ;
valvulis tenuibus ; natibus elevatis, acutis ; dentibus cardinalibus obsoletis, laterali-
bus binis ; margarita luteo-albd.

Shell rather compressed, longitudinally and obsoletely striate, transversely and mi-
nutely wrinkled, dove ccloured, on the umbones furnished with reddish angular marks ;
valves thin ; beaks elevated, pointed ; cardinal teeth obsolete ; lateral teeth two ; nacre
yellowish white.

Habs. -<:s
My Cabinet.

Diam. 1:4, Length 2-9, Breadth 3-4 inches.

Shell subtriangular, nearly equilateral, rather compressed, longi-
tudinally and obsoletely striate, transversely and minutely wrinkled,
dove coloured, furnished on the umbones with reddish angular marks ;
substance of the shell thin and fragile; beaks elevated, pointed, touch-
ing; ligament short and thick; epidermis thin; cardinal teeth obsolete
or wanting; lateral teeth two, rather long, straight, and disposed to be

112 ON THE NAIADES,

lamellar; cicatrices smooth, impressed, showing the mark of their ad-
vancement; palleal impression indistinct, broad; cavity of the shell
rather shallow ; cavity of the beaks angular; nacre yellowish white and
shining.

Remarks.—This is certainly a very interesting shell. It is difficult
to find any one to compare it with. On the inside of the anterior
margin there appears to be a disposition to crenulation, caused by the
longitudinal striez. Its habitat I am not acquainted with, having pur-
chased my specimens at a dealer’s in Europe, who could not inform
me from what country they came.

To spinosa. Plate XIX. fig. 79.

Testa obtuse turritd, lata, corned, sub epidermide fasciatd, spinis magnis ; an-
Sractibus septenis ; apertura elongata, dimidium longitudinis testxz habente.

Shell obtusely turrited, wide, horn colour, under the epidermis banded, furnished
with large spines ; whorls seven ; mouth elongate, one half the length of the shell.

Hab. Holston River, Washington County, Virginia. Professor
Troost.
My Cabinet.
Cabinet of Professor Troost.
Diam. 1:2, Length 2-2 inches.

Remarks.—This species resembles very much the Jo fusiformis
(nobis), Fusus fluviatilis (Say), but may be distinguished by its large
transversely compressed spines, the fusiformis having somewhat longi-
tudinal tubercles. I am not acquainted with any fluviatile shell which
has such large spines (there being about seven on each whorl), nor any
which has such a general resemblance to a marine shell. Professor
Troost informs me they are rare in the river, that they had been
observed in the graves of the aborigines; and as it was generally be-

AND OTHER FAMILIES. 115

lieved that these were “conch shells,’ consequently coming from the
sea, it was urged that the inhabitants who possessed them must have
come over the sea. It does not appear that they had been observed
in their native element, though living at the very doors of the persons
who had remarked them in the tumuli.

Patupina Burroventana. Plate XIX. fig. 80.

Tesld turritad, tenebroso-corned, transversim striata, striis majoribus duabus
vel tribus circiter medium anfractum ; suturis profundis; anfractibus senis, valde
converts ; apertura rotundatd, alba.

Shell turrited, dark horn colour, transversely striated, having two or three large
stris about the middle of the whorl; sutures very deep; whorls six, very convex:
mouth round, white.

Hab. Island of Luconia. Dr Burrough.
My Cabinet.
Cabinet of Dr Burrough.
Cabinet of the Academy of Natural Sciences of Philadeiphia.
Diam. 1:2, Length 1-8 inches.
Operculum thin, light brown.

Remarks.—This is perhaps the largest species of Paludina which
has yet been observed. It is remarkable for the numerous fine trans-
verse striz which are subgranose or undulated, and which cover, in some
specimens, the whole of the whorls. About the middle of the whorls
there are several larger striae, the largest being always, in the specimens
examined by me, immediately above the suture. I owe to Dr Bur-
rough’s great kindness the opportunity of describing this species.
During his late voyage he procured it, with many other fine shells,
from the vicinity of Manilla, in the island of Luconia.

VOL. V.—2 D

114 ON THE NAIADES,

Read before the American Philosophical Society, April 18th, 1834.

Lymnza acuta. Plate XIX. fig. 81.

Testa elongato-turritd, tenui, levi, fusconigricante; spird attenuata; anfrac-
tibus senis ; apertura subovatd.

Shell elevated, turrited, thin, smooth, dark brown; spire attenuate; whorls six ;
aperture subovate.

Hab. pond four miles north of Philadelphia.
Diam. °3, Length -7 of an inch.

Remarks.—This delicate species, although attenuate, is not so much
so as the evxilis herein described. Its whorls are more convex and the
body whorl larger, the aperture being about one half the length of the
sheli. Several specimens were found by me some years since, in a
very small pond near to the Falls of Schuylkill. Since then this pond
- has occasionally dried up, and I have not been able to find others.
Although there are other ponds near to this, which other species in-
habit, I have never been able to discover the acuta in any other spot.

Lymnza Exitis. Plate XIX. fig. 82.

Testa attenuata, tenuissimd, longitudinaliter striatd; anfractibus septenis,
plano-convexis ; columella reflexd ; apertura ovato-oblonga.

Shell attenuated, very thin, longitudinally striate ; whorls seven, plano-convex ;
columella reflected ; aperture ovato-oblong.

Hab. Ohio, T. G. Lea.
My Cabinet.
Diam. :4, Length 1-5 inches.

AND OTHER FAMILIES. 115

Remarks.—This is perhaps the most attenuated Lymnza yet ob-
served in this country. It approaches most to the reflerus (Say), but
is more elongate than that species. ‘The most remarkable character of
the exilis is, perhaps, the reflection of its labium, which is not laid on
the body of the whorl. Where it joins above with the labrum, the
angle is quite acute, and is separated from the body whorl. The spe-
cimen figured was not taken alive, and the epidermis being destroyed,
the description and representation are partially defective. The aper-
ture is about two-fifths the length of the shell.

Puysa ELLIPTICA. Plate XIX. fig. 83.

Testa sinistrosd, ellipticd, tenuissimd, pellucida, castaned, nilidd; spira brevius-
cula; anfractibus quaternis ; labro marginato; apertura angustata.

Shell sinister, elliptical, very thin, pellucid, chesnut coloured, shining; spire rather
short; whorls four; outer lip margined ; aperture narrow.

Hab..... 'T..<G@iiea
My Cabinet.
Diam. -2, Length +5 of an inch
Remarks.—This species is less inflated and more of a chestnut colour
than any I am acquainted with. Its colour is almost reddish, and the
light coloured margin of the outer lip is remarkable. ‘The aperture
is rather contracted, and the whole shell somewhat elongate.

AmpuuLariA Horeronensis. Plate XIX. fig. 84.

Testa subventricosd, levi, superne subplanulatd, perforata, luteo-fuscescente,
fasciaté ; suturis impressis ; anfractibus quinis ; apertura subovata, alba.

Shell subventricose, smooth, flattened above, umbilicate, yellowish-brown, banded ;
sutures impressed ; whorls five; aperture suboyate, white.

116 ON THE NATADES,

Hab. Hopeton, near Darien, Georgia. Professor Shepard.
My Cabinet.
Cabinet of Professor Shepard.
Diam. 1-4, Length 1-7 inches.

Remarks.—I owe to the kindness of professor Shepard of New
Hayen this interesting shell. It was procured by him during his late
geological investigations in our southern states, with other shells, de-
scriptions of which will be found in these memoirs. It resembles the
A. fasciata (Lam.), but is less globose, the whorls of our species being
somewhat flattened on the side and top. It differs from the 2. depressa
(Say), described in major Long’s expedition to St Peter’s river (subse-
quently changed to .2. paludosa in the Disseminator), in being less
globose, and in being flatter on the side and superior part of the whorls.

Patupina Groratana. Plate XIX. fig. 85.

Testa ventricoso-conoided, tenwi, tenebroso-corned, levi; suturis valde impressis :
anfractibus instar quinis, convexis ; aperturd subrotundatd, alba.

Shell ventricoso-conical, thin, dark horn coloured, smooth ; sutures very much im-
pressed ; whorls about five, convex ; aperture nearly round, white.

Hab. Hopeton, near Darien, Georgia. Professor Shepard.
My Cabinet.
Cabinet of Professor Shepard.
Diam. -7, Length 1-1 inches.

Remarks.—This species, in form, resembles most, perhaps, the P.
vivipara. It is not quite so large, nor has it bands. It is rather more
elevated, and the body whorl is smaller and rounder than the P. decisa
(Say). The aperture at the base recedes more than is usual with this
genus.

66 fHelvemna

57

”

60 ..
C2 ae
62 35
6s ,

lens
DULCHETVETINA

VITO LILF«Aa
MUS CULTUM

purpuragila
umn reguls

MOmnoahontia

CUCCOSWOTHE

64 Hele
ao

66,

67

68

69

7o

1 Paldudoia

PL.XIX,VoLd

mameilla
hiaphana
Hiumalanua
VESTCH
cincta
Noodiana
wlobula

bt mondifer:

MAL
LAINIE LL
Welaniopet:
drtculs
Cuctostoma
Achatttec

7

tOULEUS
wnpertadt
PIINCEPS
macilala
Puxctqgila
Irtatn

Vo

LUE MLONSE

spinosa

Ww Paludina

81 /aymnaca
S25

85 Plasa

84 Ampullarta
85 Paludina
SG Succinea

» ,
Burrough
aula

eutler

Miptica

Mopelone

GOTULAN

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AND OTHER FAMILIES. ) i

Succinea reETusA. Plate XIX. fig. 86.

Testa ovato-oblongd, tenuissimd, pellucida, flaviduld ; spird brevi; anfractibus
(obaed
ternis ; aperturd inferne dilatatd et retractd.

Shell ovately oblong, very thin, pellucid, yellowish; spire short; whorls three ;
aperture below dilate and drawn back.

Hab. Ohio, near Cincinnati. ‘T. G. Lea.
Diam +3, Length +7 of an inch.

Remarks.—< single specimen only of this species has come into my
possession. It differs so much from any of the described species, in
the dilatation and retraction of the inferior part of the aperture, that I
have not hesitated to consider it new.

VOL. V.—2 E

SYSTEMATIC INDEX

OF

THE SHELLS DESCRIBED IN MR LEA’S MEMOIRS ;

Unio acutissimus” -

anodontoides
angustatus = -
arceformis -
asper - -
asperrimus = -
ater - -
Blandingianus
brevidens -
Burroughianus
ealceclus -
camelus -
eapillaris -
capseformis
castaneus -
eirculus -
eeruleus =
Congareus -
confertus -
Conradicus -
Cooperianus
Corrianus -
cuprinus -
decisus =
divaricatus = -
donaciformis
dromas =
ebenus =
elegans -
ellipsis -
emarginatus
fabalis -

VOLUMES III., IV. AND V.

Vol. IV. 89

- IV. 81
- IV. 114
- IV. 116
- TVies85
- In. Al
- III. 426
- V. 101
- 1 ey 3)
- V. 67
- Hil. 265
- V. 102
- V. 29
- Wiens
- LV 9
- Ill. 433
- UV ee 95
- DVeee
- V. 103
- Vv. 63
- Vee iGl
- V. 65
- IV. 94
: TVie 92
2 V. 64
- III. 267
- Ve 70
- IV. 84
- IVeees3,
- III. 268
- V. 62
- Wee 86

Unio formosus
fulvus

geometricus

glans -
Grayanus

Griffithianus
Haysianus
heterodon

Tlildrethianus

ineurvus
iris -
irroratus

Kirtlandianus

lacteolus

lacrymosus
lanceolatus

lens =

modioliformis

multiplicatus
multiradiatus
multistriatus
Murchisonianus

Nashvillianus
Nicklinianus

obesus
oecidens
olivarius
oriens

Paranensis
parallelopipedon

patulus
perdix

Oks #

SYSTEMATIC INDEX OF MR LEA’S MEMOIRS. 119
‘ »

Unio perplexus ae Volo TV. 112 Symphynota ochracea Vol. IIT. 455
pileus - - - EVs 019 tenuissima - III. 453
pictus - - - Vv. 73 Woodiana - V. 42
planulatus - - - Til. 431 Cyrena Jayensis - - - * YV.108
pustulatus - - - IVs “79 rotundata : - Vo 10%
pustulosus - - - IV. 76 turgida—- - - Ve 109
pyramidatus - - IV. 109 Woodiana - - V. 110
Ravenelianus - . V. 32 Aphrodite columba - - Viel
rubiginosus - - III. 427 Helix Caroliniensis = - - IV. 102
Schooleraftensis - Vi 3% cincta - - - V. 56
securis - - - Ill. 437 cyclostomopsis - - V. 53
Shepardianus - - V. 95 diaphana- - - V. 54
soleniformis - - IV. 87 globula - - - V. 58
Sowerbianus - - Vv. 68 Himalana_ - - - V. 55
suleatus - - - IIL. 430 mamilla —- - - V. 54
stapes - - - BVien va monodonta - - V-. D3
subovatus = - - - IV. 118 muscarum - - V. 51
subglobosus - - Vv. 30 ovum-reguli - - V. 52
subrotundus - - LV V7 purpuragula - - Vee 5
Taitianus — - - - Vinod vesica - - - V. 56
trapezoides - - IV. 69 Woodiana - - Vv. 57
trigonus - - - IV. 110 Carocolla Helicoides - - IV. 103
Troostensis - - Ved spinosa . - IV. 104
varicosus—- - - IV. 90 Helicina lens - - - Vv. 49
Zig-Zag - - - III. 440 pulcherrima = - - Vv. 49

Anodonta Blainvilliana - Vira a7, virginea . - Vv. 50

Burroughiana . V. 105 Achatina Vanuxemensis - V. 84
Ferussaciana - V. 45 Sueccinea retusa - - - V. 117
incerta - - Vv. 46 Auricula fuscagula - - V. 83
lato-marginata = V. 76 Cyclostoma striata - - V. 84
Mortoniana~ - - V. 80 Physa elliptica = - s - V.115
plana - - - Vv. 48 Lymneza acuta - - - V. 114
Stewartiana - - V. 47 exilis - z: = V.114
tenebricosa- - Vv. 78 imperialis - - Vv. 81
Margaritana Raveneliana - V. 106 Melania aculeus - - Ve ST
Symphynota alata ow Ill. 448 acuta - = = IV. 101
Benedictensis — - V. 104 elongata - - IV. 120
bi-alata - IT. 445 subularis - - IV. 100
bi-lineata - - LV. 98 tuberculata —- - IV. 101
compressa - IIL. 450 Io fusiformis - - - IV 122
cygnea- - IIL. 456 spinosa - - - V.. 112
complanata - Ill. 448 Melanopsis maculata - - V.. 82
discoidea - - \ ez) princeps - - V. 82
globosa- - Vv. 41 Paludina bi-monilifera - - V. 58
gracilis - - TIT. 452 . Burroughbiana - Vie DLS
inflata - - IV. 99 Georgiana - - V. 116
levissima - Ill. 444 Ampullaria Hopetonensis - Weel

magnifica - V. 43

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