924 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [NoV. 29, 



Crag, Belgium, S.W. & S. France, Italy, Greece, Algeria. Post- 

 tertiary : Scandinavia, British Isles, Calabria, Rhodes ; 0-50 ft. 



M. triangula (Renier), Brocchi, and many other synonyms. M. 

 lateralis of Say is closely allied, if it be not a variety of the present 

 species. 



I subjoin a description of the animal of a small variety from 5 to 

 7 fathoms in Balta Sound, Shetland : — Body pale yellowish-white : 

 mantle having its edges fringed with numerous short cirri, which 

 are slightly tubercular at their tips : tubes conical, rather short, 

 covered for the greater part with a leathery sheath, separate at their 

 extremities, minutely speckled with bistre ; orifices encircled by two 

 rows of cirri, the outer cirri being longer and thicker than those 

 forming the inner row, which latter are usually bent back on the 

 margin of the sheath ; all these cirri are more or less tubercular at 

 the tips ; valve of upper tube large and hyaline : foot white, tongue- 

 shaped, long, and finely pointed. 



\, 3. Mactra stultorum, Liuue. 



M. stultorum, L. S. N. p. 1126: B. C. ii.p. 422; v. p. 188, 

 pi. xliii. f. 4. 



' Porcupine ' Exp. 1 809 : St. 2, Lough Swilly, L. Foyle. 1870 : 

 Med. Adventure Bank (fragment). 



Distribution. S. Norway to Egypt and Black Sea, Adriatic, 

 Mogador, Canaries ; 0-35 fms. Not Red Sea, as given by Ehren- 

 berg. 



Fossil. Upper Tertiaries : British Isles, Italy. 



I. Lutraria rugosa, Chemnitz. 



Mactra rugosa, Chemn. Conch. -Cab. vi. p. 236, t. 24. f. 236. 



' Porcupine ' Exp. 1870 : Atl. St. Vigo B. Valves rather abundant 

 on the shore, as well as at Cadiz, whence Chemnitz received it. 



Distribution. Lusitauian coasts, Gibraltar, various parts of the 

 Mediterranean on the European and African shores, Mogador, 

 Canaries ; 0-4 fms. According to Messrs. Adams the only habitat 

 for this shell is the coast of Guinea ! 



Fossil. Miocene : Vienna and Bordeaux Basins, Switzerland. 

 Upper Tertiaries : Bracklesham, Biot, Italy, Greece, Rhodes. Post- 

 tertiary : Selsea. 



It is the type of Gray's genus Eastonia ; but there is no sufficient 

 character to separate it from Lutraria. 



I 2. Lutraria elliptica, Linne. 



Mactra lutraria, L. S. N. p. 1126. 



L. elliptica, B. C. ii. p. 428, pi. viii. f. 3 ; v. p. 188, pi. xliv. f. 1. 



'Porcupine' Exp. 1870 : Med. St. 50. 



Distribution. Norway to Malta and the Morea, Adriatic ; 0-22 

 fms. 



Fossil. Upper Tertiaries : Coralline and Red Crag, Belgium, 

 S.V4''. France, Italy, Morea. Post-tertiary : Lancashire, Scotland, 

 Calabria, Rhodes. 



