GASTEROPODA. 221 



Eburna, Lamarck. Ivory- shell. 



Etymology^ ehur, ivory. 



Synonym, Latrunculus, Gray. 



Type, E. spirata. PI. Y., Eig. 11. 



Shell umbilicated when young ; inner lip callous, spreading 

 and covering the umbilicus of the adult ; operculum pointed, 

 nucleus apical. 



Distribution, 9 species. Eed 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. PI. Y., Fig. 15. 



Shell like bucckium ; columellar lip callous, expanded, form- 

 ing a tooth-like projection near the anterior canal. Operculum 

 ovate, 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. N. ohsoleta (Say) lives within the 

 influence of fresh water and becomes eroded. N. reticulata, L., 

 is common on the English shores at low water, and is called the 

 dog- whelk by fishermen. 



JDistrihution, 210 species. Low water — 50 fathoms. "World- 

 wide. Arctic, Tropical, and Antarctic Seas. 



Fossil, 19 species. Eocene — . Britain, &c. North America. 



Sub-genus, Oyllene, Gray. C. Oweni, PI. Y., Fig. 17. Outer 

 lip with a slight sinus near the canal ; sutures channelled. 

 "West Africa, Sooloo Islands, Borneo. Fossil, Miocene, Touraine. 



Cydonassa, Swainson. C. neritea, PI. Y., Fig. IQ. 



Phos, Montfort. 



Etymology, phos, light. 



Synonym, Phinodomus, Sw. 



Type,V. senticosus, PI. Y., 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.) Eed Sea, Ceylon, Philip- 

 pines, Australia, West America. 



