OF NEW SOUTH WALES. 57 



Hab. Cape York, near Albany Island, North Australia, 11 

 fathoms, sandy mud bottom ; Darnley Island, Torres Straits, 

 30 fathoms, sandy mud. 



This species is six ribbed near the apex, finely striated below, 

 as Mr. Sowerby expresses it. The specimens before me have 

 very fine thread-like ribs ; the number of ribs in all are from 24 

 to 25, and 6 at or near the apex ; shell thin, white, slightly 

 arched. 



9. — Dentalium bisexangulatum. 



Dentalium bisexangulatum, Sowerby, Thes. Conch., Vol. 3, p. 

 102, pi. 223, fig. 8. 



Hab. Cape Grenville, North-East Australia, 20 fathoms, mud 

 bottom ; Cape York, North Australia, 11 fathoms ; Warrior 

 Reef, West side. Torres Straits, 8 fathoms, hard mud ; Darnley 

 Island, 25, 30 fathoms, sandy mud bottom ; Sue Island, Torres 

 Straits, 11 fathoms. 



A white shell, with 12 ribs, the notch in the apex very small ; 

 some specimens do not show it whatever. 



10. — Dentalium hexagonum. 



Dentalium hexagonum, Gould, Sowerby, Thes. Conch., vol. 3, 

 p. 103, pi. 233, fig. 10. 



Hab. Cape York, North Australia, 11 fathoms, sandy mud; 

 Katow, New Guinea, 8 fathoms ; Darnley Island, Torres Straits, 

 30 fathoms, sandy mud ; North America. (Gould) China and 

 Singapore. (Sowerby.) 



11.— Dentalium septemcostatum, n. sp. 



Shell white, slightly arched, 7-ribbed, ribs somewhat sharp, 

 having finer ones between, extending from the base to the centre, 

 interstices with fine transverse silk-like stria?, apex perforated, 

 perforation with a minute notchlike fissure on the dorsal margin, 

 aperture circular, entire. 



Length, 7 lines ; diam. apex, J ; base, f line. 



Hab. Evans' Bay, Cape York, North Australia, 6 fathoms, sand 

 bottom. 



