ACADEMY OF NATURAL SCIENCES. 183 



The specimens are preserved in the collection of the Survey; most of them appear 

 to be very rare in "a living state, though I have encountered several of them in the 

 later Tertiary deposits, especially in the Post Pliocene. 



MUREX, Linn. 



5. G. Muricidea, Swains. 



M. Barbarensis, G. 



M. t. uuicolor, fusca ; varicibus V-IX, haud magnis ad angulum auctis ; varix ul- 

 tima praelata ; anfractu primo laevi, anfractibus V supra recte truncatis, infra pa- 

 rum convexis ; tota superficie liris spiralibus et squamosis induta ; apertura sub- 

 elliptica, intus lactea ; labio incrassato, polito ; labro extante, tuberculis intus 

 ornata; canali interdum recto, interdum recurvato. 



Long. -77, lat "46, long. aper. 2, long, canal -24. 



Shell small, brown; whorl six, the first smooth, the remainder angulated, hori- 

 zontally or a little concavely truncated above and very slightly convex below the 

 angle ; varices variable, from five to nine, usually about six or seven to a whorl, 

 angular but not very prominent, except on the angle, where they are sometimes 

 prolonged into long recurved processes, in other cases only making a prominent 

 angular tubercle; the whole surface is covered with strong revolving ribs, crossed 

 foy fine squamose plates; aperture sub-elliptical, lips prominent, white within, the 

 outer lip with five or six tubercles internally, last varix forming a broad lateral 

 expansion to the lip ; canal closed, straight, or more usually a little recurved. 



Hab. Catalina Island, 40 fins., and Santa Barbara Channel, 20-30 fins. Dr. 

 Cooper. 



Nob. 515 b, c and d, Mollusca, Survey Cabinet. 



PLEUROTOMA, Lam. 1799. 



Turris, Bolt. 1798, not Turris, Hump, 1797. 



S. Gen. Surcula, H. & A. Ad. 



P. PERVERSA, G. 



P. t. sinistra, unicolor, rufo-brunnea; sub-fusifoiinis; anfractibus XI vel XII 

 laevibus rotundato-compressis ; apertura angusta, labio tenui, acuto. 



Long. 12, lat. 35, long. aper. - 45. 



Shell sinistral, elongate sub-fusiform, apex acute, sometimes slightly bent, nu- 

 clear whorls two, very convex, loosely twisted and white ; whorls, eleven or 

 twelve, slightly convex ; color a light reddish brown, somewhat lighter on the 

 middle of the whorl; aperture narrow, canal short, inner lip moderately encrusted 

 with a white callus, brown on the outer margin; columella twisted; outer lip 

 acute, sinus rounded, shallow, broad and adjoining the suture. 



Hab. Catalina Island, 60 fms., Dr. Cooper. Also fossil, not rare, in the P. 

 Pliocene at San Pedro. One specimen from that locality is two inches long. 



No. 1020, Mollusca, Survey Cabinet. 



P. (S.) Carpenteriana, G. 



P. t. fusiforrais ; anfractibus VIII, prope suturam concavis ; tota superficie con- 



