232 Dr. Gwyn Jeffreys on Arctic 



mark, 40-150 fras. (Lov^n, Sars) : White Sea and coast's of 

 Russian Lapland (Middendorff) : Gulf of St. Lawrence, 150 

 fms. (Whiteaves) : ' Porcupine ' Expedition, 1869, 420-512 

 fms., young; 1870, Bay of Biscay, 257-539 fras., young: 

 Arctic Expedition, 5|-35 fras. (Feilden and Hart). 



Fossil. Tangy Glen, W. Scotland {Robertson and Cross- 

 key) : E. Scotland, 30-40 ft. deep : Elie, a few ft. below the 

 surface (Jamieson). 



The shell is certainly not " equi valve," as Sowerby de- 

 scribed it. It is the P. vitreus of Gray in the * Supplement to 

 the Appendix of Parry's First Voyage,' but not Chemnitz's 

 species of that name. 



Leda pernula, Muller. 

 Area ptmula, Miill. in Beschaftigungen naturf. Freunde, vol. iv. p. 35. 



Yar.faleula. Shell sickle-shaped, longer (from the beak 

 to the front margin) and flatter than the variety Jachsonii of 

 Gould or huccata of Steenstrup ; the " rostrum " or point is 

 short, blunt, and more or less upturned in the adult ; front 

 margin curved. 



St. No. 1 (Moss). 



Recent. Spitzbergen (Torell, Eaton) : Wellington Channel 

 (Belcher). The typical form and other varieties inhabit both 

 sides of the North Atlantic as well as the North Pacific, at 

 depths of from 20 to 150 fms. : ' Porcupine ' Exp. 1869, 

 251 fms.; 1870, Bay of Biscay, 305-517 fms.: 'Valorous' 

 Exp. 15-175 fms. : Arctic Exp., 6\ fms. (Feilden). 



Fossil. Post-tertiary or "glacial " beds in the North of 

 England, N. Wales, Ireland, Scotland, Scandinavia, and 

 Canada, surface to 320 ft. : Moel Tryfaen, 1330-1360 ft. 

 (Darbishire). 



Variable in shape and sculpture. Having many synonyms, 

 or polyonomatous. 



Leda jrigida^ Torell. 



Yoldia frigida, Tor. Bidr. t. Spitzbergens Molluskfauna, p. 148, t. 1. 

 f. 3 (1859). 



St. No. 3 (Feilden). 



Recent. Spitzbergen, 30-60 fms., and Greenland, 250 

 fms. (Torell) : Iceland (Mus. Copenhagen) : Finmark, 200- 

 300 fms. (Sars) : Shetland, 60 fms. (J. G. J.) : Gulf of St. 

 Lawrence, 150 fms. (Whiteaves) : ' Porcupine' Exp., 1869, 

 114-1360 fms. ; 1870, Bay of Biscay, 227-1095 fms. : 'Valo- 

 rous' Exp., 175 fms. 



Yoldia nana of M. Sars. 



