362 VENERID^E. 



My largest specimen measures two and a half inches in 

 length by three inches in breadth : others are twisted 

 and irregular or keeled on the posterior side. 



The habitat assigned by Linne' to Venus decussata is 

 "O. Indico"; but the description in the ' Mus. Ulr. 

 Keg./ as well as those in the 10th and 12th editions of 

 the ' Syst. Nat./ suit the European shell which now 

 bears the above specific name. Specimens from the 

 Indian Ocean cannot be distinguished from this in 

 form, sculpture, or colour, although they are called T. 

 Indica. The synonyms are numerous; I have noted 

 about a dozen. If the name could now be changed, I 

 would suggest the adoption of that proposed by Da 

 Costa, viz. " rdiculatus" Adanson's " le Lunot " ap- 

 pears to be the present species, and not T. pullastra. 



Genus III. LUCINOFSIS *, Forbes and Hanley. 

 PL VII. f. 1. 



BODY roundish: mantle having its edges furbelowed or 

 puckered : tubes separate throughout. 



SHELL globose, thin, striated concentrically : lunule in- 

 distinct : teeth, in the right valve three, and in the left valve 

 two cardinals, besides the usual lateral in each valve : pdllial 

 scar exhibiting a remarkably deep sinus. 



To the learned authors of the ' British Mollusca ' is 

 the credit due of proposing and establishing the present 

 genus, which connects the Veneridae with the Tellimda, 

 and almost forms the type of an intermediate family. 

 In the structure and position of the siphonal tubes it is 

 more like Tellina than Venus and in the orbicular form 

 of the shell, as well as in the number and shape of the 

 teeth, it differs from any genus in either of the above- 



* Having the aspect of the genus Lucina. 



