50 



For this new and rare fpecies we are alfo indebted to the 

 indefatigable zeal of Mr. L^skey, v/ho took it by the dredge 

 off St. Abb's head, in the Frith of Forth. 



The general appearance of this fliell is lo like fome 

 varieties of Donax mis, that it might readily have pailed 

 undillinguifhed by more than a common obferver, but it 

 could not efcape the critical eye of the Icrutinizing concho- 

 logift by whom thefe flieets arc ib copioufly enriched. The 

 only living fpecimen that gentleman was fo fortunate to 

 procure was that from which the defcription and figure were 

 taken. 



The fpeclfic diflin6lions from that of Donax iriis ( which 

 ought probably to be placed amongft the Veneries) are the 

 clofenefs of the Jlrice, want of the thin membranaceous 

 ridges, and the teeth of each valve being equal in number, 

 and even at their tips, as well as the replication of the mar- 

 gin. The two laft chara6lers are particularly eflential in 

 difcrimination, as D. irus is fo fubje6t to variation in growth, 

 but invariably (if perfecSl) pofleffes two bifid teeth in each 

 valve, independent of a plain tooth in one of the valves. 



CFIAMA. 



Cor. This very rare fhell as a Britijh produ6lion we are happy 

 p. 134. to remark has been recently taken alive by Mr. Laskey, in 

 p. 579. the Frith oi Forth, by dredging o^ St. Abb's head. 



ARCA. 



