ball: mollusca and brachiopoda. 277 



Smaller, more slender, and with a distinctly more excavated fasciole than in 

 the last species which also has the keel usually nodulous. In the better pre- 

 served specimens the spiral sculpture is continued in front of the keel while 

 in the two preceding species it is confined to the anal fasciole. 



Borsonia (Borsonella) saccoi Dall, n. ep. 



Shell much eroded, solid, short, chalky, with an olive-gray periostracum and 

 over five wliorls ; spire short, conic, nuclear wliorls lost ; the anal fasciole de- 

 pressed, forming a constricted concave band near the posterior edge of the whorl 

 which is thickened and marginate ; on the anterior side of the fasciole the shoulder 

 of the whorl forms tlio periphery on which are (thirteen on the last whorl) short, 

 rounded, wavelike nodules or axial ribs which are slightly protractive and do not 

 extend over the base; the other axial sculpture is composed of rather marked 

 elevated, more or less irregular lines of growth ; on the fasciole and base these 

 are more or less obscured by spiral impressed lines with much wider interspaces, 

 which appear feeble and as if obsolete where not eroded ; canal short, straight ; 

 outer lip simple with the sulcus near the suture, rather wide and deep when com- 

 plete ; body with a white callus and near the insertion of the pillar a single very 

 strong sharp edged spiral plication extending into the spire. Lon. of (eroded) 

 shell, about 14 ; of aperture, about 7 mm. ; max. diam. about 7 mm. 



U. S. S. " Albatross," station 3354, Gulf of Panama, in 322 fathoms, mud, 

 bottom temperature 46° F. U. S. N. Mus., 123,105. 



Although this specimen is so imperfect it is clearly distinct from any other col- 

 lected in the region and is therefore worthy of description. It differs from the 

 otliers in its stronger ridge in front of the suture, its fewer, longer, and more per- 

 sistent ribs. The plication on the pillar extends fully to the columellar callus, and 

 is quite conspicuous. 



Borsonia (Borsonella) coronadoi Dall, n. sp. 



Plate 14, figure 2. 



Shell slender, acute, pinkish white, with a pale brown periostracum and about 

 ten whorls ; spire longer than the aperture, the nuclear whorls smooth, turgid, 

 the subsequent turns carrying a rounded low keel, usually in front of the middle 

 of the whorls forming the siiirc, the area between which and the suture is flatly 

 impressed, the whorl in front gently rounded ; on some of the early whorls the 

 keel is slightly undulated, but not regularly nodulous ; besides the lines of growth, 

 both the fasciole and the anterior part of the whorl show indications under a lens 

 of obscure regular distant spiral striae, and are also more or less marked with a 

 faint vermicular reticulation of the surface ; suture not appressed, distinct; aper- 

 ture narrow, anal sulcus deep and wide, reaching tiie suture; outer lip thin, 

 sharp, arcuately produced; inner lip slightly eroded, polished, with no callus; 



