MOLLUSCA. 85 
ber of hinge teeth, and the longitudinal ribs, readily distin- 
guish it from the genus Venus. It is very limited in recent 
species. 
Another genus instituted by Lamark, and termed by him 
Capsa, has two teeth in one valve, and a bifid tooth in the 
other, the type of which he considered to be the donax lavi- 
gata of Gmelin. 
It was in the construction of the characters of the genus 
Venus that Linnzus unfortunately indulged in obscene al- 
lusions. It is now time that the pages of natural history 
were freed from such pollution. Other names, more expres- 
Bie: can easily be substituted, alike advantageous to the in- 
terests of science, and the reputation of the illustrious Swede. 
11. Seonpyxius.—The shells which Linnzeus included 
under this head are usually denominated prickly oysters. 
The genus represented by the S. gederopus of Linnzus. 
The S. plicatula of the same author has been separated 
from the spondyli, and placed in a new genus, under the 
name PrrcatuLa. This genus differs from the former in 
the valves wanting ears, and in the absence of the triangu- 
lar unisulcated space at the teeth of the under valve, so 
characteristic of the parent genus. 
12. Cuama.—This is by no means a well constituted 
genus in the Linnzan system, as it includes shells possess- 
ing very different characters. It has, accordingly, under- 
gone several important alterations. Bruguiére proceeded 
so far by establishing two new genera, and Lamark, follow- 
ing the same plan, has added three more to the number. 
Those shells, which now belong to the genus CHAMA, are 
irregular, inequivalve, and adhere to other bodies. The 
hinge contains only one thick oblique tooth. 
It is repre- 
sented by the chama Lazarus of Linneus. 
