56 



greatly inleresting that some recent species have been found, which fall into this group. They 

 are nearly all from the deep-sea. 



Key to species. 



I. Transverse striae distributed over the whole surface. Length 60 — 75 mill. 



about 14 — 15 times the greatest diam trachcatiim. 



II. Transverse striae only near the apex, shell anteriorly smooth. 



a. Length 60 — 75 mill., about 11 — 12 times the greatest diam. . . . semitracheahim. 



h. Length 22, diam. 2 mill subtor quatum. 



c. Length 20 mill., about 12 — 13 times the greatest diam mnilosiim. 



67. Dentaliuin sciiiitrachcatum n. sp. PI. IV, figs 20, 21. 



Stat. 45. 7°24'S., 118° 15'. 2 E. Flores Sea. 794 Metres. Fine grey mud. 6 Spec. 



Stat. 284. 8°43'.i S., 127° 16.7 E. Timor Sea. 828 Metres. Grey mud. i Spec. 



Stat. 300. io°48'.6S., 123° 23'.! E. Timor Sea. 918 Metres. Fine grey mud. 2 Spec. 



Stat. 314. 7°36'S., 117° 30'. 8 E. Flores Sea. 694 Metres. Fine sandy mud. 2 Spec. 



Diagnosis. A beautiful big white shell, well-curved, tapering, sculptured near the apex 

 with many extremely fine, close rings as in D. tracheatiini. This ringed appearance remains 

 visible over a distance of about one sixth to one seventh of the shell's length. The .shell then 

 becomes smooth, with many superficial growth striae, and with at regular distances some deeper 

 incised lines. They give the shell a faintly "segmented" appearance, each "segment" measuring 

 about 0,3 mill. Apex entire, simple, thin-edged. Anterior aperture circular, rather oblique. 

 Length 75 mill., diam. of ant. aperture 6,5 mill. 

 Length 71 mill., diam. of ant. aj^erture 6,5 mill. 

 Length 45 mill., diam. of ant. aperture 5 mill. 

 Length 58 mill., diam. of ant. aperture 6 mill. 



Remarks. Superficially this shell resembles big specimens oï D. 2csitafuiii, hut is easily 

 distinguished by the transversely ribbed apex. 



68. Dentalmvi tracheatuni n. sp. PI. IV, fig. 22. 



Stat. 45. 7°24'S., 118° 15.2 E. Flores Sea. 794 Metres. Fine grey mud, with some radiolariae 



and diatomes. 3 Spec. and a fragment. 



Stat. 208. 5°39'S., 122° 12' E. Banda Sea. 1886 Metres. Solid green mud. 3 Spec. and some 



fragments. 



Stat. 271. 5°46'.7 S., 134° o' E. Arafura Sea. 1788 Metres. Bluish green mud of a uniform 



appearance. 10 Spec. 



Stat. 300. io°48'.6S., I23°23'.i E. Timor Sea. 918 Metres. Fine grey mud. 4 F"ragments. 



Stat. 314. 7° 36' S., 117° 30'. 8 E. Flores Sea. 694 Metres. Fine sandy mud. One fragment. 



Diagnosis. Shell long, cylindric, very slightly curved, extremely fragile. Sculpture : the 

 entire surface from apex to anterior aperture with close-set minute rings, reminding one the 

 structure of an insect's trachea. Posteriorly the rings are very close and slightly raised ; near 

 the anterior aperture, especially in old specimens, the incised lines get a little further out each 



