I 



DALL : MOLLUSCA AND BRACHIOPODA. 267 



come less prominently sculptured and the ribs almost obsolete; aperture and 

 canal short and wide ; pillar with little callus, straight, solid ; outer lip produced, 

 thin, sharp, simple ; anal sulcus wide, shallow, in the older shells nearly reaching 

 the suture. Length of shell, about 18 + ; of last whorl, 11.5 ; of aperture, 8.0; 

 max. diam. 7.0 mm. 



U. S. S. "Albatross," station 3360, Gulf of Panama, in 1672 fathoms, sand; 

 bottom temperature 42° F. U. S. N. Mus. 123,091. 



This species when old and eroded can hardly be distinguished from G. esuriens 

 in the same condition, but fortunately specimens of the young shells in good con- 

 dition could be compared and show obvious and sufficient characters proving the 

 distinctions between the two species. 



Gemmxila benthima Dall, n. sp. 



Plate 1, figure 7 ; Plate 13, figure 4. 



Shell solid, with a conspicuous greenish-gray periostracum, ten-whorled, with the 

 spire longer than the aperture, biconic, usually much eroded ; nucleus lost in all the 

 specimens ; subsequent whorls appressed at the suture, in front of which is a strap- 

 like revolving ridge with (on the fifth whorl twenty-two) low nodules, eacb one cor- 

 responding to a feeble, strongly retractive, lamella-like riblet, which becomes prom- 

 inent again as a semilunate nodule on the anal fasciole which forms the periphery 

 of the whorl ; between the fasciole and the presutural band the whorl is a little 

 excavated; on the anterior side of the fasciole the whorl is rounded, with more or 

 less alternated low spiral threads stronger near the periphery, where the suture is 

 laid on the second thread, and diminishing toward the canal ; the interspaces are 

 decidedly wider than the threads, which become more or less obsolete on the last 

 whorl ; the surface is also more or less reticulated by fine spiral striae and ele- 

 vated lines of growth, giving it a rough aspect ; last whorl much the largest ; the 

 anal fasciole situated a little above the normal periphery of the whorl, but by its 

 own prominent sculpture becoming peripheral ; the sulcus is narrow and square- 

 cut ; outer lip thin, simple ; body with a white callus which extends forward upon 

 the very short, obliquoly truncate but not pervious pillar, which is slightly re- 

 curved ; operculum normal, large, brownish. Lon. of shell, about 28 -I- (decollate) ; 

 of aperture, 14 ; max. diam., 12 mm. 



II. S. S. " Albatross," station 3392, off the Gulf of Panama in 1270 fathoms on 

 hard bottom, temperature 36°.4 F. U. S. N. Mus. 123,089. Also at stations 

 2807, 3360, 3365, 3366, 3376 and 3413, in from 812 to 1360 fathoms, sand or 

 ooze, temperatures 36° to 42° F. in the Gulf of Panama, the adjacent coast of 

 Ecuador, and the Galapagos Islands. 



This species is a typical Gemmula, with a narrow anal sulcus situated in the 

 peripheral carina, an oval operculum with apical nucleus and concentric lines of 

 increase, and uodose periphery. It is usually badly eroded. 



