1879.] 'lightning' and 'porcupine' EXPEDITIONS. 557 



Distribution. Arctic seas in both hemispheres, southwards to 

 Bergen and Connecticut, N. Japan ; 2-150 fins. 



Fossil. Pliocene and Post-tertiarv. Scandinavia, Scotland, Russia, 

 Gulf of Naples (B. C. v. p. 16G), Messina; 20 fms.-4/O ft. 



4. Pecten pes-felis, Linne. 



o Ostrea pes-felis, L. S. N. p. 1146: Chemnitz, Conch. -Cab. vii. 

 t. 64. f. 612, t. 65. f. 613. 



' Porcupine ' Exp. 1870 : Tangier B. (young). 



Distribution. G. Gascony to Morocco, Mediterranean, Adriatic, 

 jEgean, Madeira, and Canaries, ' Challenger ' Exp. (Fiji Islands); 

 18-110 fms. 



Fossil. Pliocene, Italy, Morea, and Rhodes. 



5. Pecten pes-lutr.e, Linne. 



Ostrea pes-lutrce, L. Mant. Plant, p. 547. 



P. septem-radiatus, B. C. ii. p. 62 ; v. p. 166, pi. xxiii. f. 1, la. 



'Lightning' Exp. : St. 2, 4, off Faroe I. (very large valve). 



'Porcupine' Exp. 1869 : St. 3, 6, 15, 23, 23«, 25, 65. 1870: 

 Atl. 1, 2, 3, 6 (var. alba), 8, 9, 10, 13, 16, 17, 26-30; Med. Capo 

 de Gata, Cartagena B., G. Bona, Beuzert Road, Rasel Amoush, G. 

 Tunis, Adventure Bank, off Rinaldo's Chair. 



Distribution. Finmark to the Sea of Marmora, and the Adriatic ; 

 10-300 fms. 



Fossil. Pliocene and Post-tertiary. Scandinavia, Great Britain 

 and Ireland, Belgium, Vienna Basin, S. France, Africa, Italy, aud 

 Rhodes ; 0-440 ft. 



There are at least a dozen synonyms for this variable species, 

 including P. septemradiatus, Miiller, Ostrea inflexa, Poli, and P. 

 dumasii, Payraudeau. The last named variety agrees more nearly 

 with Linne" s description of Ostrea pes-lutrce in having very small 

 ears, " Auriculce vix ullaa s. altera minuta." The Linnean name 

 appears to have been first recognized and adopted by the late M. 

 Gay in his ' Catalogue des Mollusques du Departement du Var,' 

 1858. The editors of the 'Journal de Conchyliologie ' object to 

 compound names of species ; but we have the great authority of 

 Linne for many such names. As to the names of species derived 

 from English persons, unnecessary confusion is avoided by using 

 their ordinary compound names, e.g. Wyville-Thomson, the simple 

 surname Thomson being very common and belonging to several 

 naturalists. 



6. Pecten sulcattjs, Midler. 



P. sulcatus, Midi. Zool. Dan. Prodr. p. 248. 



P. aratus, B. C. ii. p. 64 ; v. p. 167, pi. xcix. f. 5. 



' Lightning ' Exp. : Station 4. 



« Porcupine ' Exp. 1869: St. 13, 14, 25, 65. 1870: Atl. 1, 2, 

 3, 24-30 ; Med. 45, Capo de Gata, Adventure Bank. In some 

 specimens, as well from the Atlantic as from the Mediterranean, the 

 ribs are more knotty or tuberculous than in others. 



