120 MR. SOWERBY, JUN., ON NEW SPECIES OF SHELLS. [Jan. 1", 



6, sloping, scarcely convex ; nucleus smooth ; last whorl somewhat 

 swollen, contracted towards the base. Aperture oblong, dark brown 

 within. Lip with a moderate sinus above, denticulated within. 

 Canal very short. Columella with a nodulous callosity above. 

 Length 4, width 2 millim. 



Hab. Florida, on Ostrea virginica (Melvill). 



Mr. Melvill found specimens of this shell as noted above in 1872, 

 and in 1879 gave the species the above name in manuscript in his 

 collection ; but the shell has not I believe been hitherto described. It 

 is allied to C. nigricans, but smaller and quite different. 



FissuRELLA MELviLLi, sp. uov. (Plate V. iig. 1 1 .) 



Shell oval, rather elevated, broad behind, slightly contracted in 

 front ; radiately closely ribbed, ribs very little raised, alternately 

 larger ; concentrically wrinkled ; pale green, interior greyish white. 

 Orifice round, subcentral. Margin shghtly irregularly wrinkled. 

 Length .50, width 40, height 22 millim. 



Differing from its congeners chiefly in the rotundity of its orifice. 



Pecten SIBYLLA, sp. nov. (Plate V. fig. 12.) 



Shell thin, suborbicular, acutely elevated at the umbones, equi- 

 lateral, equivalve. Colour light orange, concentrically faintly banded 

 with darker orange. Upper valve slightly convex, lower somewhat 

 flatter ; both valves very finely and closely ribbed, ribs very delicately 

 serrated. Right auricle narrow, extending to about a quarter of the 

 length of the shell from umbo to margin ; left auricle moderately 

 broad. Alt. 58, lat. .56 millim. 



A very beautiful species with delicate sculpture ; the ribs are very 

 numerous and close-set, varying slightly and promiscuously in size, 

 not regularly alternating as in some species. The delicate close-set 

 scales cover the whole of the ribs. 



The specimen passed from the collection of the late Thomas Lombe 

 Taylor into that of Mr. Melvill, who gave it the above name in 

 manuscript. 



Pecten loxoides, sp. nov. (Plate V. fig. 13.) 



Shell rather thin, obliquely subovate, inequilateral, white, with 

 the upper valve transversely undulately streaked, and spotted with 

 pinkish orange. Lower valve rather deep, upper shghtly convex. 

 Radiating .ribs 20 in number, prominent, rounded, smooth ; inter- 

 stices about equal in width to the ribs, also smooth. Auricles 

 small, the right rather larger than the left. Alt. 25, lat. 24 millim. 



Hah. Australia. 



The valves of the specimen are odd ; there are also odd valves of 

 the same species in the British Museum. The species is quite unhke 

 any hitherto described, and may be easily recognized by the obliquity 

 of its outline. 



CoNus textile, vai.VEUETRios. (Plate V. fig. 6.) 



Compared with C. cahonicus (Brug.), more pyriform and atten- 



