PLATE LXIV. 



In referring this ambiguous Shell to the Tellina genus, we may 

 incur censure, as it does not certainly possess every characteristic t)f 

 a Ullen, yet we conceive less impropriety in altering the genera than 

 in retaining it as a trigonella. 



This Shell has been admitted as the Venus borealis of Linnams 

 and from the Synonyms of Lister's figure, not without probability. 

 We do not, however, think the Linnaean descriptions agree suffi- 

 ciently with our Shell ; it may be a variety of it, though we hesitate 

 to admit it as such. 



Pennant has described this Shell twice, the old Shell is Tellina 

 Crassa, No. 28, and the young one Venus borealis, No. 52 of that 

 author ; he adds indeed " the Tellina crassa has the habit of Venus 

 borealis, but its sides are unequal, one being more extended than the 

 other." 



Da Costa has been under similar difficulties, he gives it as a species 

 of his genus trigonella, though he savs in the general description, 

 that " the hinge of this kind is of a different structure from the 

 Trigonella, for it consists of two minute, thin, plate-like, pa- 

 rallel teeth, aside of which is a large triangular cavity, and has no 

 lateral teeth." 



Common on several of the English shores. 



