150 CLASS III. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
Pl. CCVII. Fig. 9 and 10. 
PyRAMIDELLA DOLABRATA, Lamarck, Anim. sans vert., vol. vi. part 2. 
p- 222. Chemnitz, Conch., vol. v. pl. 167. f. 1603 and 1604. En- 
cyclopédie Méthodique, pl. 452. f. 2. a, b. 
Trochus dolabratus, Linnzus. 
Bulimus dolabratus, Bruguiére. 
Family 6. TURBINACEA. 
Testa turbinata, seu conoidea, seu turriculata, anfractibus nunc con- 
fertim, nunc laxé volutis. Operculum vel corneum, vel testa- 
ceum. 
The family of the Turbinacea corresponds as nearly as possible with 
the two genera Trochus and Turbo of Linnzus ; but the species which 
have been added to this group since his time present a sufficient diver- 
sity of character for the formation of thirteen good generic divisions, 
completing the phytophagous or plant-eating series of the class. The 
form we have adopted for this family is precisely that in which it was 
first introduced by Lamarck, as we see no necessity now for the altera- 
tion which he subsequently made of associating the genera Delphinula, 
Scalaria and Vermetus in a separate family under the new title of ‘‘ Les 
Scalariens.” He was induced to distinguish these genera thus on ac- 
count of the loose manner in which the whorls of their shells are coiled 
in comparison with those of the rest of the family ; this character, how- 
ever, is so much more prominently developed in the shell of Vermetus 
than in that of Scalaria or Delphinula, that, since it has been found ne- 
cessary to remove the Vermeti to another part of the system, the sepa- 
ration is no longer required. De Blainville has founded new families 
upon the two primitive divisions of Lamarck ; the Trochi are taken as 
the type of the first under the title of the Goniostomata ; and the Tur- 
bines as the type of the second, under that of the Cricostomata; but in 
