• I 



14 MOLLUSES FROM WEST COAST OF AMERICA— BALL. vol.xviii. 



intersections iii well developed specimeus, the spines at the shoulder 

 much longer than the others, while in some depauperate specimens the 

 only spines are at the shoulder; there is also some obscure spiral stria- 

 tiou between the threads on the last whorl, and the lines of growth are 

 irregular and often prominent; aperture subtriangular, with three 

 strong- plaits on the pillar, and, in fully adult shells, some faint liratiou 

 inside the outer lip; canal short, distinct, forming- a strong- fasciole 

 around a narrow, deep umbilicus, over which the inner lip is partly 

 reflected; body with a wash of callus; throat whitish. Height of shell, 

 35; of last whorl, 25; of aperture, 18; width of shell exclusive of tlie 

 spines, I'O mm. 



IT. S. Fish Commission station .3308, in ()(» fiithoms, near Cocos Island, 

 (iulf of Panama. 



Type.—^o. 122900, U. S. N. M. 



This is the most thorny species yet described. 



CANCELLARIA lO, new species. 



Shell fusiform, solid, whitish or pink, with a more or less olivaceous 

 epidermis, and about six whorls; spire i)oiiited, whorls rounded, some- 

 what constricted in front of the suture, which is appressed; sculpture 

 of numerous flattened spiral threads, with about equal interspaces, 

 uniform over the whole surfiice, but with occasional finer intercalary 

 threads; these are crossed by (on the last whorl about 13) rather stout, 

 rounded ribs, strongest at the shoulder, obsolete beyond the periphery^ 

 and not reaching the suture behind them; aperture rather long-, outer 

 lip simple, smooth, not reflected or lirate; pillar rather straight, with 

 three strong plaits; canal sliallow, wide, pointed, making no percepti- 

 ble fasciole; umbilicus none; body with a thin wash of callus. Height 

 of shell, -43; of last whorl, 33; of aperture, 25; width of last whorl, 

 21 mm. 



U. S. Fish Commission station 3354, in 322 fathoms. Gulf of Panama. 



This species has much the look of a gigantic Admete., but without 

 the arched pillar. .Most of the specimens were eroded, and the species 

 has a genuine abyssal aspect. 



PLEUROTOMA (STEIRAXIS) AULACA, new species. 



Shell large, solid, white, fusiform, with about five whorls (nucleus 

 eroded) covered with a pale straw-colored epidernns; whorls rounded, 

 with rather distinct lines of growth crossed by numerous very sharp, 

 narrow, prominent^ subequal spiral ridges with about equal or nar- 

 rower interspaces; the periphery is foruied by a sort of rib, on which 

 stand two to four similar keels, but smaller than the others and more 

 crowded; in front of the rib there is a faint constriction of the whorl; 

 the keels are less prominent on the canal, which is moderately longand 

 recurved; on the penultimate whorl there are about 14 keels between 

 the sutures; aperture elongate, reflecting the sculpture, but without 



