230 ARCADE. 



The longer beaked variety occurs on both sides of Scot- 

 land, as in Loch Fyne (Barlee) ; and Aberdeen (Mac- 

 gillivray). 



This shell ranges through the Scandinavian and Arctic 

 Seas, and is found fossil in our Pleistocene strata, but not 

 commonly, and occurs in the red crag of Sutton (S. V. 

 Wood). 



L. pygm.ea, Munster. 



Minute ; surface quite smooth. 

 Plate XL VI I. fig. 10, and (Animal) plate P. fig. 3. 



Nucula pygrruea, Munster in Goldfuss. Pet. Germ. pi. 12.5, f. 17 (fossil). — 

 Philjpfi, Moll. Sicil. vol. ii. p. 46 (fossil). — S. Wood, Mag. 

 Nat. Hist new series, vol. iv. p. 298, pi. 14, f. 7 (fossil). 

 „ tenuis!, Philippi, Moll. Sicil. vol. i. p. 65, pi. 5, f. 9 (fossil). 

 „ gibbosa, Smith, Wern. Mem. vol. viii. pi. 2, f. 10 (fossil). 

 „ lenticula, Moller, Index Moll. Groenlandire, p. 17 (from types). 

 Leda pygmcea, Forbes, Mem. Geolog. Survey, vol. i. p. 419. 

 „ tenuis, Jeffreys, Annals Nat. Hist. vol. xix. p. 313. 

 Yoldia pygnuea, Loven, Index Moll. Skandinav. p. 35. 



This minute shell, one of the more recent additions to 

 our Fauna, was first incidentally recorded as a living inha- 

 bitant of our seas in the " Memoirs of the Geological Sur- 

 vey of Great Britain." 



It is of a triangular-oval shape, subequilateral, more or 

 less ventricose (especially near the umbones), not particu- 

 larly thin, quite smooth, and covered with a very pale 

 yellowish olive-coloured and highly lustrous epidermis. 

 The ventral margin is gently but decidedly arcuated, 

 ascending in a convex line at both extremities, but rather 

 the more so at the longer side, with whose upper edge it 

 forms a short and subrostrated extremity, of which the tip 

 is bluntly acuminated. This portion is not beaked in the 



