580 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Julie 17, 



inside smooth and polished ; edge sharp and plain : scars indistinct. 

 L. 0-225, B. 0-35. 



'Lightning' Exp.: St. 3. 



'Porcupine' Exp. 18G9: St. 23, 23a, 65. 18/0: Atl. 3, 9, 17, 

 17«. 



Distribution. Norwegian arctic Exp. 1878; 459-778 fms. 



Differs from L. jeffreysi in its somewhat greater size, being at all 

 ages much broader in proportion to the length (and consequently 

 more extended on each side), the anterior end not being upturned, and 

 in the hinder margin being sharp-edged and pinched up. 



18. Leda micrometrica, Seguenza. 



L. micrometrica, Seg. Nuc. terz. mer. d'lt. p. 21, t. iv. f. 22, 

 22 a-c. 



'Porcupine' Exp. 1869: St. 23a. 1870, Med. 55. Valves only. 



Distribution. Sciacca, Sicily. 



Fossil. Pliocene. Trapani near Messina. 



I had previously given to this minute but distinct species the name 

 oblonga, by which Monterosato called it. 



19. Leda expansa, Jeffreys. (Plate XLVI. fig. 4.) 



L. expansa, Jeffr. in Ann. and Mag. N. H. Nov. 1876, p. 431. 

 'Porcupine' Exp. 1869 : St. 16, 30. 

 Distribution. ' Valorous ' Exp. ; 690-1750 fms. 



, 20. Leda insctjlpta 1 , Jeffreys. (Plate XLVI. fig. 5.) 



Shell transversely oval, equilateral, rather convex, moderately 

 solid, semitransparent, and glossy : sculpture, numerous and regular 

 but minute and fine concentric impressed striae, which become stronger 

 towards the front and are wanting at the back : colour white : epi- 

 dermis pale yellowish : margins sinuous at the back owing to the 

 prominence of the beaks, equally rounded on both sides, and curved 

 in front : beaks central, prominent : cartilage and pit minute, the latter 

 sunken : hinge-line forming a very obtuse angle : hinge-plate rather 

 broad: teeth small, sharp and comb-like, deflected outwards, 8-10 

 on each side of the beak ; they are placed on the inner side of the 

 hinge-plate : inside lustrous, microscopically fretted, plain-edged : 

 pallial and muscular scars rather distinct, the former being broad. 

 L. 0-075. B. 0-1 15. 



'Porcupine' Exp. 1869: St. 16. 1870: Atl. 16, 17, 17a. 



Differs from L. expansa in shape, convexity, and sculpture. 



21. Leda pusilla 2 , Jeffreys. (Plate XLVI. fig. 6.) 



Shell roundish-oval, equilateral, somewhat compressed, remark- 

 ably solid for its size, opaque and glossy : sculpture, numerous and 

 close-set concentric and very fine microscopic striae, which cover the 

 whole shell : colour whitish : margins rounded on every side, except 

 at the back so far as the continuity is interrupted by the beaks, con- 



1 Engraved. 2 Tiny. 



