1879.] 'lightning' AND 'porcupine' EXPEDITIONS. 565 



lenger ' Exp. (W. Patagonia and off Japan); 10-775 fms. Herr 

 Friele informs me that by sinking a dredge in Osterfiord, almost 

 perpendicularly, to the depth of 350 fathoms, he has brought up 

 this grand and beautiful species, with also living specimens of My~ 

 tilus edulis and Littorina rudis, and that L. excavata attaches itself 

 by a strong byssus to rocks close to the shore. 



Fossil. Pliocene and Post-tertiary. Norway, Altavilla?, and 

 Sicily. 



Apparently L. solida of Calcara. 



Family V. Aviculid^e. 

 l/ Avictjla hirtjndo, Linne. 



Mytilus hirundo, L. S. N. p. 1159. 



A. hirundo, B. C. ii. p. 95 ; v. p. 170, pi. xxv. f. 6. 



'Porcupine' Exp. 1870: Atl., St. 10, 13, off C. Sagres, 27, 28, 

 28a, 36, Tangier B. ; Med. off Jijeli, Rasel Amoush. 



Distribution. Southern coasts of England to the Adriatic and 

 iEgean, Madeira, Canaries, Azores ; 0-205 fms. 



Fossil. Pliocene. Coralline Crag, S. Italy. 



One of the two specimens still preserved in the Linnean collection 

 of shells as " Mytilus fiirundo,' is certainly the present species. In 

 the ' Systema Naturae' the first reference is to the ' Mus. XTlr. Peg.,' 

 where the description agrees with the European species, although no 

 habitat is given ; the second reference is to Lister's ' Hist. Conch.,' 

 who cites D'Argeuville for the vernacular name " Dattici," used by 

 the Genoese. Lamarck called the species A. tarentina and A. at- 

 lantica, describing the former as " valvis sequalibus," and the latter 

 (more appropriately) as " valvis inaecmalibus." 



Pinna rudis, Linne*. 



Pinna rudis, L. S. N. p. 1159 : B. C. ii. p. 99, pi. iii. f. 1, and 

 frontispiece; v. p. 170, pi. xxvi. 



'Porcupine' Exp. 1870: Atl., St. 13, Vigo B., off C. Sagres", 

 Gibraltar B., Tangier B. ; Med. 50, 50 a, Rasel Amoush. 



Distribution. Great Britain and Ireland to the Adriatic and 

 Morea, Madeira, Canaries, and Azores ; 0-80 fms. 



Fossil. Pliocene. Coralline Crag (fragments), Belgium, Italy, and 

 Rhodes. 



There is no end of synonyms. Poli, Payraudeau, Phiiippi, and 

 many other conchologists of repute have adopted the Linnean name 

 rudis. The shape and sculpture are extremely variable. 



Family VI. Mytilid^e. 

 1. Mytilus edulis, Linne. 



Mytilus edulis, L. S.N. p. 1157: B. C. ii. p. 104, pi. iii. f. 2; 

 v. p. 171, pi. xxvii. f. 1. 



'Porcupine' Exp. 1870: Atl. St. Vigo B. and Gibraltar B. 

 Valves only. 



