LEDA. 231 



young, but simply attenuated and rounded. The extremity 

 of the opposite side, which is rather the shorter and some- 

 what tapering, is unsymmetrically rounded ; the upper 

 edge, except near the very prominent umbones, is convex 

 and moderately sloping. The declination of the other 

 dorsal edge is likewise but moderate, its general inclination 

 is retuse ; in the young, however, it is even slightly con- 

 vex. The beaks are small and inflected, scarcely inclining 

 to the longer side. There is not even a rudimentary lunule, 

 and the opposite dorsal area is neither impressed nor flat- 

 tened. There are about a dozen teeth on each side of the 

 hinge-margin ; the cartilage pit is very small : the inner 

 margin quite entire. 



Few specimens much exceed a fifth of an inch in length, 

 and a full eighth of an inch in breadth. 



The animal is of a pale fawn-white colour. The margins 

 of the mantle are freely open in front, closed posteriorly to 

 form a short tube consisting of the united siphons, of which 

 the branchial appears shortest : the orifices of both are 

 plain. The foot is hatchet-shaped and wide-grooved at its 

 posterior edge, to form an expanded and crenated disk. 



The discovery of this interesting little Leda as a living 

 inhabitant of the British seas, is due to Mr. M'Andrevv, 

 who dredged it first in the Sound of Skye on a muddy 

 bottom, twenty-five to forty fathoms deep ; off Croulin 

 Island in thirty fathoms ; and in fifty fathoms in the 

 Minch. It has since been taken off Skye by Mr. Jeffreys 

 and at Portree, Mr. Barlee, and by the latter gentleman 

 at Stornoway in the Outer Hebrides. 



Loven finds it on the Scandinavian Coast from Bolmslan 

 to Finmark; and Moller, who first noticed it as a living 

 species, discovered it in the Greenland Seas. As a fossil it 

 has been better known ; occurring in the Newer Pliocene 



