452 FISSURELLIDiE. 



Philippine Archipelago, principally dredged from ten to 

 twenty-five fathoms water. The genus is easily recognised 

 by the position of the perforation. 



Species of Riinula. 



Blainvillii, Defr. exquisita, A. Adams. 



carinata, A. Adams. propinqua, A. Adams. 



Genus EMARGINULA, Lamarck. 



Mantle-margin simple, reflexed over the edges of the 

 shell, anal siphon with prominent, membranous margins 

 projecting from the fissure in the shell ; foot with a rudi- 

 mentary, operculigerous lobe. 



Shell oval, conical, surface radiated or cancellated ; 

 apex entire, recurved posteriorly ; aperture oval, expanded, 

 the front edge fissured, the fissure continuous with a groove 

 which extends as far as the vertex. 



Syn. Emarginulus, Montf. .? Palmarium, Montf, 



Ex. E. rosea. Bell, pi. 51, fig. 9. Shell, E. crassa, 

 Sowerby, fig. 9, a. 



The angulated sides of the anal siphon are seen, in the 

 living animal, projecting from the fissure in the front 

 margin of the shell ; the operculigerous lobe exists in the 

 form of a single, central cirrhus on the hind part of the 

 foot. Most of the species are from considerable depths, 

 while the species of Fissurella, on the contrary, are chiefly 

 littoral. Australia, the West Indies, and the Philippines 

 harbour the greatest number, a iew only being inhabitants 

 of temperate climates. 



