568 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Julie 17, 

 1 . MODIOLARIA MARMORATA, Forbes. 



Mytilus marmoratus, Forb. Mai. Mon. p. 44. 

 Modiolaria marmorata, B. C. ii. p. 122, pi. iii. f . 3 ; v. p. 171, 

 pi. xxviii. f. 1. 



' Porcupine' Exp. 1869 : St. 9, the Minch. 18/0 : Atl. Vigo B., 

 Tangier B. ; Med. Cartagena B., Capo de Gata, Adventure Bank. 



Distribution. Bergen to Smyrna, Adriatic, Mogador, Gulf of Suez 

 and Persian Gulf, Canaries, N. Pacific, perhaps S. Carolina as Cre- 

 nella lateralis of Say ; 10-150 fms. 



Fossil. Pliocene and Post-tertiary. Coralline and Bed Crag, Bel- 

 fast, Belgium, Italy. 



Cantraine's specific name subpicta has precedence of marmorata 

 by three years ; and that given by Say, lateralis (if applicable to the 

 present species), is still older; but marmorata is now in general use. 



<- 2. Modiolaria discors, Linne. 



Mytilus discors, L. S, N. p. 1 159. 



Modiolaria discors, B. C. ii. p. 126 ; v. p. 171, pi. xxviii. f. 3. 



'Lightning' Exp.: St. 1, 3. 



Distribution. Arctic ocean in both hemispheres, * Valorous ' 

 Exp., Iceland to Guernsey, west coast of France, Piedmont, iEgean, 

 N.E. America from Labrador to Cape Cod, and N. Pacific south- 

 wards to Oregon and Japan ; 0-1785 fms. 



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

 Vienna Basin?, N.E. America; 0-100 ft. 



Modiola Icevigata and snbstriata of Gray and Modiola Icevis of 

 Beck are varieties of the present species, and connected by inter- 

 mediate gradations with the typical form. 



3. Modiolaria nigra, Gray. 



Modiola nigra, Gray, Suppl. to App. to Parry's first voyage, 

 p. ccxliv. 



Modiolaria nigra, B. C. ii. p. 128 ; v. p. 171, pi. xxviii. f. 4. 



' Lightning ' Exp. : St. off the Faroe Isles. 



'Porcupine' Exp. 1869: St. off Lerwick. 



Distribution. "With M. discors as arctic, Iceland to the Dogger 

 bank, Holland ?, N.E. and N.W. America, Novaya Zemblia, Sea of 

 Okhotsk; 7-350 fms. 



Fossil. Post-tertiary. Iceland, Norfolk ?, Scotland, N.E. America. 



This may have been the Mytilus striatulus of Linne" s ' Mantissa,' 

 as Beck supposed ; but the term " unidentato " makes it doubtful. 

 It is the Modiola nexa of Gould. 



4. Modiolaria stjbclavata, Libassi. 



Modiola subclavata, Lib. Mem. Conch, foss. in Atti Pan. iii. (1859), 

 p. 13, f. 7. 



'Porcupine' Exp. 1870 : Atl. St. Vigo B., Tangier B. Valves 

 only. 



