576 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [June 17, 



Distribution. Circumpolar in the N. Atlantic and Pacific, Novaya 

 Zemblia, Jenissei B., 'Valorous' Exp., Norwegian arctic Exp. 

 1878, Iceland, Finmark; 5-1333 fms. 



Fossil. Post-tertiary or " glacial." Norway and Sweden, Scot- 

 land, N.E. America; 60 fms.-70 ft. 



Nucula glacialis, Leach ; N. truncata, Brown ; N. portlandica, 

 Hitchcock ; N. siliqua and N. sulcifera, lleeve. 



6. Leda messanensis, Seguenza. 



L. acuminata, Jeffr. in Ann. & Mag. N. H. July 1870, p. 69: 

 Seguenza, Nuculidi terziarie merid. d'ltal. (R. Acad. Line. 1877, 

 separate cony), p. 15, t. iii. f. 15, 15 a-e. 



'Porcupine' Exp. 1869 : St. 3, 15, 16, 23, 42. 1870: Atl. 1, 2, 

 3, 3a, 6, 9, Vigo B., 22, 24-, off C. Sagres, 25-34, 36; Med. 55, 

 Adventure Bank. 



Distribution. 'Valorous' Exp., W. Norway, Mediterranean, 

 'Josephine' Exp. (Azores), 'Challenger' Exp. (between Azores 

 and Bermuda) ; 100-1750 fms. 



Fossil. Pliocene. S. Italy. 



Body clear white : mantle having its edges protruded and pout- 

 ing ; these are plain or slightly jagged, and not ciliated : tubes sepa- 

 rate ; the upper tube is cylindrical and long, and has two minute 

 tubercles at the point, one above and the other below : foot exten- 

 sile, and shaped like that of its congener. 



The shell is variable in length, and is wholly or partly marked 

 (especially in front) by close and regular concentric striae. 



After I had published the specific name acuminata, I found that 

 it had been preoccupied for an Oolitic species, the Nucula acuminata 

 of Von Buch, which is also a Leda. I have therefore substituted 

 in the case of the present species Professor Seguenza's MS. name 

 messanensis. Eichwald's L. acuminata is L.fragilis. 



7. Leda ptjstulosa, Jeffreys. 



L. pustulosa, Jeffr. in Ann. & Mag. N. H. Nov. 1876, p. 430 ; Seg. 

 Nuc. terz. p. 17, t. iii. f. 17, Ma-d. 



'Porcupine' Exp. 1869 : St. 16, 19, 20, 21, 23, 23a, 28, 30, 31, 

 58. 1870 : Atl. 2, 3a, 17a, 27, 30. 



Distribution. 'Valorous' Exp., 1450 fms. 



Fossil. Pliocene. S. Italy. 



8. Leda frigida, Torell. 



Toldia frigida, Tor. Spitzb. Moll. p. 148, t. i. f. 3. 



'Porcupine' Exp. 1869: St. 9, 23a, 28, 31, 36. 1870: Atl. 

 1, 2, 3, 3a, 6, 9, 16, 22, 24, 26-34. 



Distribution. Spitzbergen, ' Valorous ' Exp., Novaya Zemblia, 

 Norwegian arctic Exp. 1877 and 1878, Loffoden Isles to Shetland, 

 Palermo, G. of St. Lawrence, N. Japan ; 3-650 fms. 



Fossil. Pliocene and Post-tertiary. English last arctic Exp. (N. 

 lat. 82° 33'), Norway, Iteggio and Messina. 



