1853.] 265 
(c.) U. cerinus. This species cannot be confounded with favs ; it has much 
less prominent beaks, more compressed disks, is proportionally longer, with the 
hinge and basal margins more nearly parallel, while the color of the epidermis 
and of nacre are very different. Mr. Lea seems to have hastily made them one 
species, probably without having time or inclination to compare them. 
(e.) U. complanatus, Soland. There has been some controversy respecting 
the original name of this species, but it seems clear that Solander had Say’s 
purpureus in view when he described his species. He not only remarks that it 
inhabits rivers in Maryland and New Jersey, but his description, ‘¢ ovate, com- 
pressed, with the front (posterior) margin straight, obliquely truncated towards 
the cardinal slope, hinge with the primary teeth three-sided and striated,” applies 
very well to a common variety of Say’s purpureus. If Solander’s name had 
been founded alone on the figure in Lister, t. 150, fig. 5, it could not be retained, 
because the species intended to be represented by that figure will probably ever 
be disputed; and it represents U. niger, Raf., much better than the shell in 
question. Lamarck even quotes it for erasstdens, (Lea’s trapezotdes,) which it 
certainly does not resembles The words “ admodum crassus,’’ engraved on 
Lister’s plate, prove that it was an exceedingly thick shell, and a Western 
species. 
(f.) U. clava. Kuster has quoted Rafinesque’s figures 23 and 24 for his gzbbosa, 
which is a nodulosus species not figured on any of his plates. Those figures 
represent U. scalenia. 
(g-) U. nodiferus, Con. Mr. Lea considers this identical with prasinus. 
Since I have compared several specimens with a fine series of the latter species, 
I see little resemblance between them. The nodiferws is a smaller, more ven- 
tricose and inequilateral shell, and the large tubercles grouped together about 
the middle of the disc, are never seen in prasinus. The latter has the slightly 
prominent tear-shaped tubercles Jike the young guwadrulus, very dissimilar in 
number, shape and prominence to those of the zodiferws. Three specimens of. 
the latter, from Alabama, are in the collection of the Academy. 
(h.) U. ochraceus, Say. T. 157, fig. 12, in Lister’s Conch., is usually referred to 
Anodonta cataracta of Say, but it much better agrees with the Southern variety 
of U. ochraceus. The color, ‘ subruber,’’ does not agree with any of our Ano- 
dontas, and, moreover, Lister names it Pecruncutus, under which general term 
he includes Galathea, Paxyodon and Cyclas, which is sufficient evidence that 
his Pectunculus fluviatilis had well defined teeth. The cardinal teeth of the 
Southern ochraceus being distinctly striated, would account for the name of 
Pectunculus being applied to it. Besides, it will be observed that Lister com- 
mences the Anodontas with the heading of ‘‘ Section 2d, De musculis cardine 
levi,’? which includes three species. His Section 3d then commences under 
the heading of “ Pectunculus.”? This is proof positive that his t. 157, fig.912, 
is not an Anodonta. 
(i.) U. obliquus, Lam. Mr. Lea has referred Barnes’ wadatws to this species, 
but Lamarck’s description is wholly inapplicable to wndatus, which is not 
oblique, and certainly not “ ovate-rotundate.” The error probably originated 
in Barnes’ citation of Lamarck’s species with a mark of doubt, as synonymous 
with wndatus. 
(j-) U. plexus, Con. There is a variety of this species, more elliptical, and 
with the umbo and upper part of the disc covered with closely-arranged granu- 
lations. It is possible that this may prove to be a distinct species. U. semi- 
granosus, some conchologists think the same species with U. plexus, but it 
certainly cannot be, if von dem Busch’s species is represented in Phillippi’s 
Conchyl. pl. 1, fig. 1. That is afar larger shell, and of a totally different 
character. 
(4.) U. prasinus, Con. Mr. Lea observes that Prof. Kirtland thinks this 
may prove to be a variety of pustulosus, (bullatws, Raf.) They are, however, 
