DESCRIPTIONS OF THE SPECIES OF LIMA. 233 



Art. VI. — Descriptions of the Species of the Genus Lima, from the 

 Coralline Crag, in the Cabinet of Searles Valentine Wood, 

 Esq., late Curator to the Geological Society of London. 



13, Bernard St., Russell Square, 



March lOih, 1839. 



Sir, 



During a residence of some years in the county 

 of Suffolk, I devoted the greater part of my time to collecting 

 the numerous fossils of the crag, and particularly those of the 

 inferior beds described under the name of " coralline crag" in 

 the 'Phil. Mag.' for August, 1835. The whole of my collec- 

 tion has been lately removed to the metropolis ; and as a con- 

 siderable number of the species which it contains are new to 

 science, it is desirable that figures and descriptions of these 

 should be published, as well as of those shells which have 

 been described from inferior or imperfect specimens. I there- 

 fore forward to you the enclosed MSS., and accompanying 

 series of the genus Lima, and if you think them of sufficient 

 interest for publication, with illustrations, in the ' Magazine 

 of Natural History,' I will, on a future occasion, continue the 

 description of the new species contained in my cabinet. 



Yours, «&c. 



S. V. Wood. 



Editor of the Magazine of Natural History. 



The genus Lima, Brug., is characterised as inequilateral 

 and oblique, with an opening on one side, as the passage for 

 a byssus : but there are some shells which, though they do 

 not possess all these distinctions, retain other characters in 

 common with the true Limes, and cannot with propriety be 

 entirely removed from the genus. The crag yields two spe- 

 cies, perfectly equilateral, and apparently closed bivalves, so 

 far deviating from the generic character that I have thought 

 it necessary to institute for them a sub-genus, which I pur- 

 pose to call Limatula. The Plagiostoma of Lluyd has been 

 long established, and many different species delineated by 

 Sowerby and other conchologists from the external character 

 alone; and it is but recently that a specimen has been disco- 

 vered (I understand now in the possession of Mr. J. D. C. 

 Sowerby) which shows the hinge to be the same as that of 

 Lima. Goldfuss unites Plagiostoma to Lima, and has in- 

 cluded all the species of the former in the latter genus, with 

 the exception of the Plag. spinosa, which he has altogether 

 rejected. The only difference that I have been able to ob- 

 serve between Plagiostoma and Lima is the opening which 

 Vol. III.— No. 29. n. s. 2 b 



