132 BULLETIN OF THE 



the aperture, and not forming a canal ; outer lip sinuous but not notched ; 

 epidermis thin and smooth. Soft parts ? 

 Type, Benthobia Tryonii Dall. 



Benthobia Tryonii n. s. 



Plate XXXV. Fig. 6. 



Shell with a pale brown, thin smooth epidermis, under which is a thick 

 easily eroded chalky layer, recalling that of some fresh-water shells; spire 

 short, eroded in all the specimens, but seemingly originally acute ; whorls 

 about six, exclusive of the (decollate) nucleus, full, rounded ; sculpture of sin- 

 uous lines of growth, not disturbing the polish of the surface, and faint micro- 

 scopic spiral scratches ; in front of the suture the margin of the whorl is pinched 

 up into ten or twelve obliquely radiating short waves, which may be either 

 sharp-edged or flattened, and become obsolete toward the end of the last whorl ; 

 they are slightly constricted near the suture ; base rounded, without any um- 

 bilicus or siphonal fasciole ; the eroded apices seeming perforate, it is possible 

 that the very young may be umbilicate ; aperture longer than wide, pointed 

 behind and in front, but not canaliculate; outer lip simple, receding from the 

 suture, then running parallel with the axis for a short distance, then again re- 

 ceding and arching round in front of the end of the pillar; inner lip callous; 

 columella thick, broad, concavely arched, subtruncate and rounded at the end, 

 behind which is a shallow groove and in front of which the peritreme is ex- 

 tended in a rounded point. Lon. of shell (tip eroded), 13.0; Ion. of last 

 whorl, 10.0 ; lat. of shell, 7.5 mm. 



Habitat. U. S. Fish Commission Station 2678, off Cape Fear, North Caro- 

 lina, in 731 fms., ooze, bottom temperature 38°. 7 F. 



This is a very remarkable shell, with its brownish smooth surface and eroded 

 chalky substratum it recalls a fresh-water animal and its aperture resembles 

 to some extent that of Pyrgulifera or Melanopsis, but there is no canal. It is 

 somewhat like Trichotropis except that it is smooth and has an arched columella. 

 It recalls Cancellaria or Admete, but has no umbilicus and is perfectly destitute 

 of plaits on the axis. It is impossible to determine its place until the soft 

 parts are known, but it is equally impracticable to place it in any known 

 genus from the shell characters. I suspect it is related to Admete, and leave 

 it temporarily in that vicinity. Tritia integra Conrad, also referred by him to 

 Buccinum and to Bulliopsis (subgenus of Nassa), from the Calvert Cliffs Mio- 

 cene of Maryland, may perhaps belong to this group, but I have not seen an 

 authentic specimen and judge chiefly from the figure in the Proceedings of the 

 National Institute, Plate III. Fig. 5, 1842. 



It is dedicated to the memory of that indefatigable conchologist, the late 

 G. W. Tryon, Jr. 



