NO. 22J>5. ]^EW NORTH PACIFIC MOLLUSKS—DALL. 343 



forming a sort of neck. The specimen (which was figured from life) 

 was about 150 mm. in lenj^th; its greatest diameter just behind the 

 ventral fin about 22 mm. 



Collected on the surface of the North Pacific Ocean in latitude 

 43° 10' north, and longitude 147° west, by W. H. Dall, July 23, 1866. 



SEGUENZIA CEKTOMA, new species. 



Shell small, trochiform, white, with a minute, smooth globular 

 nucleus and seven subsequent str(»ngly sculptured whorls; suture 

 obscure: spiral sculpture of a small, closely beaded thread at the 

 summit of the whorl, separated from a low, sharp carina by a wider, 

 excavated interspace, and the latter from a more prominent periph- 

 eral carina by a still wider space; on the base are three sharp threads 

 followed ])y three lower rounded threads, which approach the pillar; 

 axial sculpture of line, even, arcuate wrinkles, which, except where 

 they bead the posterior thread, are chiefly visible in the interspaces; 

 the suture is laid on the peripheral thread and between it and the 

 outer lip at the aperture is a very deep sulcus ; the outer lip is much 

 produced and its edge modified by the external sculpture, so that 

 there is a sulcus at the end of the peripheral keel, another at the 

 middle of the base, and still another at the base of the pillar, which 

 is arcuate and produced like a small plait; the base is imperforate, 

 the body with no visible glaze; height, 5; diameter, 3.5 mm. U. S. 

 Nat. Mus. Cat. No. 211167. 



Type-locality. — V. S. Fish Commission station 4337, off Point 

 Lorn a, California, in 565 to 680 fathoms, mud and gravel. 



SEGUENZIA GIOVIA. new species. 



Shell resembling the preceding species, but larger and differently 

 sculptured; nucleus minute, smooth, subglobular followed by seven 

 sculptured whorls; suture obscure, laid on the peripheral keel; spiral 

 sculpture of four narrow prominent keels, of which the second is 

 peripheral, the third marginates the base, and the fourth is on the 

 base, the interspaces much wider and becoming narrower anteriorly; 

 there are also seven closer even low thi-eads on the base with subequal 

 interspaces; the })Osterior wide interspaces are sculptured with close- 

 set fine spiral tlu-eads; axial sculp tme of numerous equal and equally 

 spaced arcuate threads, with wide interspaces, which on the upper 

 whorls bead the posterior carina, but later are chiefly visible in the 

 interspaces and extend over the whole shell; the sulcus at the aper- 

 ture next the body is shallot', the outer lip beyond it moderately 

 produced and crenulate by the sculpture, the thin and arcuate pillar 

 has a very small notch at its base, and there is a deep twisted per- 

 forate umbilicus and a thin layer of enamel on the body; height, 6; 

 diameter, 5 mm. V. S. Nat. Mus. Cat. No. 209228. 



