219 



validity, somewhat imbricating ; dotted at their convex mar- 

 gins by short, disconnected, sublenticular radial impressions, 

 more marked over the posterior part of the shell, and as 

 the shell grows larger. Internal margin non-crenulated and 

 flattened. Tooth-plate rather curved; about 14 teeth. 

 Milk-white. 



Dimensions. — Umbo-ventral, 16'5 mm. : antero-posterior, 

 15 mm. ; sectional of the closed valves, 5*5 mm. 



Locdlity. — Valves dredged off Cape Jaffa and Beachport 

 from 90, 130, 150, 200, and 300 fathoms. 



It differs from the ordinary form in the almost com- 

 plete absence of radial sculpture. 



Limopsis vixornata, s^v. nor. PI. xxvii., tig. 1. 



Shell solid, white, equivalve, nearly equilateral, trans- 

 versely orbicularly oval. Umbo acute, projecting well be- 

 yond the dorsal border, incurved. Inner margin smooth and 

 flat. External surface smooth, but for concentric growth 

 lines, which at fairly regular intervals are more valid, so 

 as to form subdistant lirae. Under the lens traces of radial 

 incisions are visible, especially over the posterior area. Car- 

 tilage pit triangular; 11 solid diverging teeth in a curved 

 series. Interior closely radially striate. 



Dimensions. — Umbo-ventral, 5*7 mm. ; antero-lateral, 

 6'4 mm.; largest, 8'1 mm. by 9 mm. Some have a short, 

 straight dorsal border, shorter anteriorly than posteriorly, 

 and with the radial impressions rather more marked. One 

 has an epidermis, worn away near the umbo, and project- 

 ing at the ventral margin for about a millimetre and a half 

 as a continuous radially striated membrane, which on the 

 surface of the shell breaks up into a hairy coating. 



LocaJitij. — Type from 45 fathoms, east of Neptune 

 Islands, with 4 valves and 1 living specimen ; from 49 

 fathoms, off Beachport, 23 valves; also at 55 and 62 fathoms, 

 off Cape Borda, and 110 fathoms off Cape Borda. 



Diagnosis. — The transversely oval shape, the prominent 

 umbo, and the unsculptured surface separate it from L. ttni- 

 soni, Ten. Woods; but possibly it is only a variant. 



Limopsis eucosmus, s^*. nor. PI. xxvii., tig. 2. 

 Shell solid, rather compressed, white, obliquely orbicu- 

 lar, slightly higher than wide. Umbos central, prominent, 

 incurved approximate. Cartilage-pit small, triangular. 

 Tooth-plate slightly curved ; teeth, 5 anterior, 6 posterior, 

 somewhat diverging. Inner margin flat and smooth. In- 

 terior obsoletely radially striate. Posterior muscle-sear large 

 and long ; anterior, short and narrow. Outer surface ex- 



