MOLLUSCA. 85 



her 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 Linnaeus 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- 

 sive, can easily be substituted, alike advantageous to the in- 

 terests of science, and the reputation of the illustrious Swede. 

 11. SPONDYLUS The shells which Linnaeus included 

 under this head are usually denominated prickly oysters. 

 The genus represented by the <S. gcederopus of Linnaeus. 

 The S. plicatula of the same author has been separated 

 from the spondyli, and placed in a new genus, under the 

 name PLICATULA. 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. CHAMA. This is by no means a well constituted 

 genus in the Linnaean system, as it includes shells possess- 

 ing very different characters. It has, accordingly, under- 

 gone several important alterations. Bruguiere 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 Linnaeus. 



