NATICIDjE. 



on prominences at the base of the tentacles. Dentition, PI. 1, 

 fig. 9. 



The Lamellariime are carnivorous, living upon Hydrozoa, 

 Alcyonaria and compound Ascidise. The eggs are deposited in 

 the midst of colonies of the latter. The first embryonic shell 

 is nantiloid, with spiral ridges ; the second is more simple, 

 resembling a Carinaria; these shells are united at their margins 

 by a thin membrane. The pelagic larval forms have received 

 the names of Brownia, Echinospira, Calcarella and JasoniUa. 

 See Manual, ii, t. 8, f. 103-105 ; Structural and Syst. Conch., i, 



130, t. 20, f. 51. 



Subfamil} 7 III. Vanikoridas. 



Shell external, white, with sometimes a velvet}' epidermis, 

 usually striated, costate or decussated ; nmbilicated, without a 

 trace of callus. Operculum thin, corneous, non-spiral. 



Animal with a long snout, tentacles flattened, much dilated in 

 the middle, narrow above ; e}-es sessile at their external base ; 

 mantle margin simple ; foot profoundly bipartite, a narrow, 

 truncated, elongated propodium and a larger, rounded or sub- 

 ({iiadrangular, operculigerous metapodium ; a large epipodial 

 veil on each side of the foot ; branchia a single row of triangular 

 leaflets, partly free. Jaws flattened; radnla short and wide, 

 having, according to Gray, two series of teeth (?). 



Synopsis of Genera. 



I. Naticinse. 



Genus NATICA, Adanson, 1757. 



Shell oval globular, porcellanous, solid, generally smooth, 

 covered by a fine epidermis, which is transparent, and generally 

 not very persistent ; umbilicated, or umbilicus more or less 

 filled with callus ; aperture semilunar, vertical, the outer lip 

 simple. Operculum large, semilunar, paucispiral, corneous or 

 calcareous. 



Animal with large cephalic lobe, truncated in front, subquad- 

 r angular. 



Subgenus NATICA (sensu stricto). 



Shell smooth, solid, brightly colored in bands, spots, stripes, 

 etc. Operculum calcareous (PI. 1, figs. 12, 13). N. canrena, 

 Linn. 



