MOLLUSCA OP THE ' CHALLENGEE ' EXPEBITION. 513 



The localities for this variety are very remarkable ; but I believe 

 the specimens are really one species, and cannot be separated 

 from D. entails, L. 



The geographical distribution is doubly interesting in connexion 

 with its extreme antiquity, which Mr. Grwyn Jeffreys (B. C. iii. 

 192), on the authority of Homes (Foss. Moll. Tert. Beck. Wien, 

 1856), carries back even to the Miocene. 



7. DentALIUM liEPTOSCELES, W. (Xe7rro(TKe\r]S.) 



St. 160. Mar. 13, 1874. Lat. 42° 42' S., long. 134° 10' E. S. of 

 Australia. 2600 fms. Eed clay. 3 specimens. 

 Animal. — Yellow, with a large dark patch in the region of the 

 liver. A close little bunch of captacula round the mantle- 

 opening. 

 Shell. — Very attenuated, thin, brilliant, porcellanous, with lon- 

 gitudinal flecks of opaque white on the translucency of the 

 shell, chiefly toward the apex where the shell thickens, very 

 little bent, very slightly compressed between the convex and 

 concave curves. Sculpture. There is some kind of flexuous 

 longitudinal texture in the structure of the shell affecting the 

 reflection from the brilliant surface, which is also closely and 

 regularly scratched transversely by very minute, sharp, but 

 superficial lines, which run round the shell a little elliptically. 

 L. 1-5. B. 0-12, at apex 004. 



This species in form very much resembles D. erectum, G. B. 

 Sow., B. M., "from Sydney," for while some specimens of that 

 species are more curved than this, others are even less so ; but in 

 this species the transverse striae are very much more oblique ; and 

 in the former there is no trace of the irregular iutratextural lon- 

 gitudinal striae which exist here. Than I), affile, Sars, this is a 

 straighter and much more cylindrical, attenuated, brilliant, and 

 delicate shell. 



8. Dentalium ciecumcinctum, W. 



St. II. Jan. 13, 1873. Lat. 38° 10' N., long. 9° 14' W. Setubal. 

 470 fms. Olohigerina-ooze. 2 young specimens. 



St. 23. Mar. 15, 1873. Sombrero Island, St. Thomas, D. W. I. 

 450 fms. Globifferina-ooze. 2 fragments. 



St. 122. Sept. 10, 1873. Lat. 9° 5' to 10' S., long. 34° 49' 

 to 53' W. Pernambuco. 350 fms. Mud. 2 fine specimens. 



