GASTEROPODA. 2D 
Esurna, Lamarck. Ivory-shell, 
Etymology, ebur, ivory. 
Synonym, Latrunculus, Gray. 
mijpee, 4. Sspirata: PI..V., Fig. 11. 
Shell umbilicated when young; inner lip callous, spreading 
and coyering the umbilicus of the adult; operculum pointed. 
nucleus apical. 
Distribution, 9 species. Red Sea, India, Cape, Japan, China, 
Australia. Solid, smooth shells, which have usually lost their 
epidermis, and are pure white, spotted with dark red; the 
animal is spotted like the shell. 14 fathoms. (Adams.) 
Nassa, Lam. Dog-whelk. 
Etymology, nassa, a basket used for catching fish. 
Synonyms, Desmoulinsia and Northia, Gray. 
Type, N. arcularia. Pl. V., Fig. 15. 
Shell like buccinum; columellar lip callous, expanded, form- 
ing a tooth-like projection near the anterior canal. Operculum 
oyate, nucleus apical. Lingual teeth arched, pectinated ; uncini, 
with a basal tooth. 
The animal has a broad foot, with diverging horns in front, 
and two little tails behind. JV. obsoleta (Say) lives within the 
influence of fresh water and becomes eroded. WN. reticulata, L., 
is common on the English shores at low water, and is called the 
dog-whelk by fishermen. : 
Distribution, 210 species. Low water—50 fathoms. World- 
wide. Arctic, Tropical, and Antarctic Seas. 
Fossil, 19 species. Hocene—. Britain, &c. North America. 
Sub-genus, Cyllene, Gray. OC. Oweni, Pl. V., Fig. 17. Outer 
lip with a slight sinus near the canal; sutures channelled. 
West Africa, Sooloo Islands, Borneo. Fossil, Miocene, Touraine. 
Cyclonassa, Swainson. O. neritea, Pl. V., Fig. 16. 
PxHos, Montfort. 
Litymology, phos, light. 
Synonym, Rhinodomus, Sw. 
Type, P. senticosus, Pl. V., Fig. 18. 
Shell like nassa; cancellated ; outer lip striated internally, 
with a slight sinus near the canal; columella obliquely grooved. 
The animal has slender tentacles, with the eyes near their 
tips. 
Distribution, 30 species. (Cuming.) Red Sea, Ceylon, Philip- 
pines, Australia, West America. 
