A DEEP-SEA MASON 279 



sort of chevaux-de-frise, formed of the dead shells of 

 other species, or of bits of shingle, or even, should no 

 other material be at hand, of bits of slag and cinder 

 shot overboard from steamships. The individual here 

 figured (Fig. 71) had, with the most reckless disregard 

 of the claims of science, appropriated to its own base 

 use the shells of three new Investigator species, 

 namely Pletirotoma congenci^ (a, Fig. 71), Pletu^otoma 

 travanco7dca {b, Fig. 71), and Drillia captiva {d, Fig. 

 71), the last being a unique ''type." 



One of the handsomest of our Indian deep-sea 

 Gastropoda is Astralhtm bathyraphe, E. A. Smith 

 (Fig. 72), whose shell is not only exquisitely sculptured, 

 but is also of a beautiful magenta colour rarely seen 

 in the shells of the deep sea. Astraliuni, like Xeno- 

 pkora, is a type that was originally discovered in 

 Japan. 



Before leaving the Gastropoda, mention must be 

 made of the curious geographical distribution of the 

 key-hole limpet Puncturella asttiriana, which has been 

 taken off the West Indies in 390 fathoms, in the Bay 

 of Biscay in 600-1100 fathoms, and at the southern 

 end of the Bay of Bengal in 609 fathoms. 



The ScAPHOPODA, or tooth-shells, hitherto dredged 

 in deep water in Indian latitudes, number six species, 

 all belonging to the genus Dentalhmi, and all living 

 on soft muddy bottoms in the neighbourhood of 

 Ceylon. One of them, Dentalium magitificum, E. A. 



