MARSHALL : NEW BRITISH MARINE SHELLS. 37 



It is like a minute Pisidium, and bears no resemblance to 

 any British species except L. sulcatnlum — in fact, Dr. Norman, 

 who has seen the shelb, pronounced them such. Like that 

 species, it is circular in shape when viewed outwardly, but 

 inwardly a slight though distinct angularity is observed at each 

 corner, imparting a slightly squarish outline ; it is glossy and 

 semi-transparent, of a pale yellowish white, the concentric striae 

 are finer and more close set, with stronger marks of growth, and 

 these striae are visible inside the valves; the margins are equally 

 rounded on all sides ; the beaks are obtuse, they do not project 

 be3'ond the outline of the shell, nor incline to either side ; there 

 is a comparatively conspicuous lateral tooth on each side of the 

 beak in each valve ; these are of the same size, and run parallel 

 with the hinge-line, which is gently curved (I could not detect 

 the " extremely minute cardinal" mentioned by Mr. Chaster) ; 

 inside iridescent ; margins plain ; scars obscure. Length, o'03 ; 

 breadth, 0-03. 



N /^ 



Figure 2. Lcpon sylu'sii, Chaster (enlarged). Guernsey. 



Than Lasaca piniiila, S. Wood, this species is more convex, 

 the striae are irregular lines of growth, the outline is somewhat 

 oblique, and the dentition is different. 



It is not, of course, the re-discovery of Limopsis pcllucidus, 

 Jeff., dredged by the author off Guernsey in 1858. That is a 

 Creiiella, of tlie size and shape of Argiopc capsula, and has not 

 since been met with in British waters. It is figured in Sowerb3''s 

 Index. 



L . sykesii comes umlex the genus Neolepion of Monterosato, 

 but what other writers prefer to consider a sub-generic section of 

 Lcpton. 



Although I have had many dredgings off the coasts of 

 Guernsey, I have only met with this species once, and I had 

 passed about a dozen valves in the examination of the material 

 before my attention was attracted to it as differing from L. sul- 

 catnlum. But I secured a live specimen and half-a-dozen valves, 



