158 ARCID^E. 



Calabrian tertiaries. Miiller's description of Area mi- 

 nuta is in every respect applicable to our shell ; and I 

 do not see why the specific name given by him should 

 be superseded by that of caudata, which Donovan long 

 afterwards imposed on the same species. Fabricius 

 appears to have found his original specimens of A. mi- 

 nuta in the crop of an eider duck, which may have picked 

 up the shells on the coast of Norway before taking its 

 return flight to Greenland. I have examined the type 

 of Macgillivray's Nucula rostrata ; and it is merely the 

 compressed form of the present species, being probably 

 the L. intermedia of Orsted, and analogous to the L. 

 complanata of Moller. M. Weinkauff gives Area minuta 

 of Fabricius as an Algerian shell ; but this appears to 

 be a mistake, because one of the synonyms cited in his 

 list is Nucula striata, Lamarck, a very different species, 

 and an inhabitant of the Mediterranean. A. minuta of 

 Brocchi (an Italian fossil) is another species, and Phi- 

 lippi has distinguished it, in the Supplement to his work 

 on the Sicilian Testacea, by the name of Nucula com- 

 mutata. 



I dredged a young live specimen and a small single 

 valve of L. pernula, in 80 fathoms, off the Shetland 

 coast, in the same ground with the slender and long- 

 beaked form of L. minuta. It is much more smooth 

 and glossy than the last, proportionally longer from 

 the beak to the front margin ; and the posterior slope is 

 flatter, and has three instead of two ridges. Not having, 

 however, obtained a full-grown specimen, I must post- 

 pone a formal introduction of L. pernula into the cata- 

 logue of British shells. 



The Area rostrata of Montagu is a tropical shell. 

 Nucula arctica of Gray (N. truncata of Brown, and N. 

 Portlandica of Hitchcock) is a fossil of the Scotch gla- 



