70 Mr. G, B. Sowerby on Hinnites. 



nearly straight. ^Vhen young the shell is perfectly regular, but 

 it generally becomes irregular by moulding itself close to the sub- 

 stance to which it is fixed, as it increases in size. 



I shall now proceed to give the characters of the five congeneric 

 species which are at present known. 



1. llinniles Cortesj/i, Defr. Diet, des Sciences Nat. torn. 21 

 p. 1G9. 



Testa crassiuscula, oblonga, valva inferiore conceutrice fim- 

 briata, valva superiore longitudinaliter radiato-muricata, spinis 

 breviusculis linguliformibus ; long. max. 5 poll.* 



Shell not very thick, oblong ; lower valve covered with fringes 

 disposed in concentric circles ; upper valve covered with short 

 linguliforin spines disposed in longitudinal rays, length (height, 

 according to Mr. Gray) 5 inches. 



This shell in its young state is very smooth, and in a slight de- 

 gree radiately striated. It is only found in a fossil state, in the 

 vicinity of Piacenza. 



2. Ilinnites Dabuisso7n. Defr. loc. cit. p. 170. 



Testa oblonga, valva inferiore concentrice striata, valva supe- 

 riore longitudinaliter confertim radiata, radiis prope marginem 

 imbricatis ; long. max. 4 poll. 



Shell oblong, lower valve covered with concentric circles, 

 which mark the numerous periods of its increase ; upper valve 

 with numerous longitudinal rays, which are imbricated near the 

 margins : length (height, according to Cray) 4 inches. 



Found in a fossil state at St. Paul-trois-Chatcaux and La 

 Chevroliere. The muscular impression in this and the last is 

 generally very distinct and large. 



3. Ilinnites glganteusA Ilinnita gigantca. Gray, in Ann. of 

 Philos. Aug. 1826. Lima gigantea. Id. in loc. cit. 



* I have given the characters of the three first as nearly as I could accord- 

 ing to Defrance and Gray; of the other two I have myself drawn up the 

 cliaracters. 



+ The term giganteus is not correctly applicable to this species, as it is the 

 smallest but one, of five here indicated. Since, liowever, it has been pub- 

 lished under this name, 1 do not consider myself at liberty to alter it. 



