194 



GENERA FIGURED IN THE PLATES, BUT NOT DESCRIBED 

 IN THE TEXT. 



Genus SEPARATISTS Gray. 



Animal; unknown. 



Shell ; turbinate, subdiscoidal, the first whorls contiguous, the last 



more or less separated ; aperture expanded, slightly angulated ; 



the margin everted, umbilicus very wide, infiindibuliform, with 



the tvhorls visible as far as the apex. 



This slightly convoluted shell represents a genus of which four species 

 have been described. The animal is not known, and the place to which it 

 has been assigned in the system, — near to Leptoconchus, among the Pur- 

 pura tribe, — seems hardly natural. 



Species. 



1. Blainvilleana, Petit. 3. Grayi, Adams. 4. laxa, Say. 



2. Chemnitzii, Adams. 



Figure. 



Separatista Chemnitzii. PI. 19. Pig. 102. Shell, showing its loosely 

 convoluted mode of growth. 



Genus PEDICULAR! A, Swainson. 



Animal ; undescribed. 



Shell ; ovate-oblong, surface irregular, radiately ribbed in the 

 young state ; spire minute ; apex lateral, inclined towards the 

 left side ; aperture very wide, channelled in front. 



A small, pink, Limpet-like shell, living attached parasitically on Mediter- 

 ranean corals like the Purpura Madreporarum, to which it is probably 

 allied. The shell is radiately ribbed in a young state, but in the adult 

 the ribs become more or less obsolete. The animal is imperfectly known. 

 Mr. Adams describes having seen a specimen in which he detected eyes at 

 the outer bases of the tentacles, and he observed that the mantle-margin 



