CHASTER : NEW MARINE MOLLUSCA FROM TANGIER. 3 



Pherusa carinata, sp. nov., PI. I., Fig. 3. 



Shell sub-cylindricalj rather thin, white, semi-transparent 

 and glossy ; sculpture consisting of very strong, sharp, spiral 

 ridges of which there are four on the body whorl, three on the 

 penultimate, and two on the second and third volutions, the 

 nucleus being smooth and polished ; 'of these ridges the upper- 

 most is the strongest ; whorls six, rather convex, shouldered 

 above by the prominent keel ; suture well defined, spire long ; 

 apex blunt and rounded ; mouth somewhat oval, narrow above 

 and dilated below ; outer lip slightly angulated b_v the upper 

 ridge, receeding very much at its upper part, expanded below, 

 the basal part being excavated by a wide shallow sinus ; pillar 

 lip somewhat oblique, reflected ; umbilical chink narrow. 

 Height, 1-8 mm. Breadth, -75 mm. 



A single specimen from shore drift. The present species is 

 interesting, affording as it does an example of a Pherusa with 

 sculpture closely approximating to that so frequent in the 

 typical Aclis. The characters of this species in other respects 

 are those of the well-known P. giilsonae, CI., which was also found 

 in the same material. The only other member of the same 

 family met with was the common species which Jefferys 

 described as Odostomia minima, for which species and the closely- 

 allied but quite distinct Jeffi'cysia cylindrica, Jeff., Monterosato 

 proposes the sub-genus Cima, a separation with which I entirely 

 concur. 



Cyclostrema pruinosum, 5/. nov., PI. I., Fig. 2. 



Shell sub-globose, whitish in colour, dull and frosted in 

 appearance, owing to the entire surface being covered with very 

 numerous, fine, close -set, flexuous striae following the direction of 

 the lines of growth ; on the umbilical area and adjoining part of 

 the base there are also numerous, much stronger spiral lines, 

 finely granulated by the striae just described ; whorls two-and- 

 a-half, convex ; suture very distinct though not deep ; spire but 

 little raised ; mouth nearly circular ; outer lip thin, presenting 

 two shallow sinuations, one at the peripher}' and one below ; 

 umbilicus rather large ; operculum like that of C. nitens. 

 Height, -85 mm. Breadth, -6 mm. 



This species was very abundant in the dredgings, many of 

 the specimens still containing the animal. The only species for 

 which it could be well mistaken is C. nitens, Phil., from which it 



