340 BULLETIN OF THE 



This genus has the spire, sculpture, and nucleus of Mathilda; the basal cord 

 is like that of Oscilla nivea ; the outer lip, though less patulous and more 

 varicose, has something about it which recalls liissoina. It is like an Oscilla 

 without columellar plaits, or like a Mathilda with a thickened and internally 

 lirate peritreme and rounded base. As far as one may judge from the charac- 

 ters of the shell alone, this genus would indicate the passage between Mathilda 

 and Oscilla ; the interrogation mark I have put before it indicates my doubt as 

 to where it should be placed. 



Peristichia toreta n. s. 



Shell slender, yellowish white, thirteen-whorled; nucleus minute, glassy, 

 set on edge, having about two turbinate whorls; spire with the suture distinct, 

 marked by a plain or slightly undulate thread behind it; behind this is a 

 strong nodulated spiral, with round nodules, then a little interval and two 

 more slightly smaller similarly nodulous spirals, adjacent to each other and 

 the suture behind them; the last whorl would show about thirty-four nodules 

 in its circuit; transverse sculpture of elevated ridges, visible in the interspaces 

 following the line of the nodules across the whorl; on the rounded base they 

 appear as strong radii; base with one strong cord with a deep sulcus outside 

 of it, and the space between it and the pillar somewhat excavated; aperture 

 ovate, pillar straight, forming almost a right angle with the lip in front of it; 

 outer lip with three strong internal lirse; body with the basal cord projecting, 

 slightly covered with enamel; outer lip swollen, varicose, and whiter than the 

 rest of the shell, its margin undulated by the external sculpture; callus joining 

 the pillar and outer lips distinct and continuous. Max. Ion. of shell, 10.75; 

 of last whorl, 3.0; max. lat. of shell, 3.0 mm. 



Habitat. Coast of North Carolina at U. S. Fish Commission Stations 2607, 

 2608, in 18-22 fms., sand, sixteen miles off Cape Lookout, bottom temper- 

 ature 73°-78° F. Charlotte Harbor, West Florida, in 2 fms., weedy bottom, 

 Dall. Key West, between tides, H. Hemphill. 



This is an extremely elegant shell, in which the relative strength of the 

 tnmsverse and the spiral sculpture varies somewhat in different individuals. 

 The sides of the spire are straight, but the whorls are distinctly marked. 



The color in very fresh specimens is a milky white, more or less clouded 

 with pale yellowish brown on the base or sides. 



Peristichia agria n. s. 



Shell small, conical, white, eight-whorled, beside a minute glassy nucleus of 

 about two whorls; sculpture of, on the last whorl, one moderate spiral in front 

 of the suture, three larger ones on the side of the whorl, the most anterior of 

 which is covered by the suture as the whorls advance, a strong cord revolving 

 on the base and entering the aperture midway between the pillar and outer 



