114 CLASS ACEPHALA. 
penetrate into a cavity of the opposite one. There is a slight 
fold near the posterior extremity of the two valves, which 
renders them unequal in that part, where they are somewhat 
open. 
The animal of the Tellina (PERONZA, Poli), like that of 
the donaces, has two long tubes for respiration and for the 
anus, which withdraw into the shell, and are concealed in a 
duplicature of the mantle. 
Their shells are generally transversely striated and deco- 
rated with beautiful colours. 
Some of them are oval and thick. 
Others are oblong and strongly compressed. 
Some, again, are lenticular, where, instead of a fold, there is 
frequently nothing but a slight deviation of the transverse 
striz. 
We might separate certain oblong species which have no 
lateral teeth, and others which, with the hinge of the telline, 
have not the fold of the posterior extremity. They are the 
TELLINIDES, Lam. 
It is necessary to distinguish from the tellin the 
LorIPEs, Poli., 
Which have the shell lenticular, the central teeth almost 
effaced, and a simple furrow for the ligament behind the 
nates. The animal is furnished with a short double tube, 
and its foot is prolonged into a kind of cylindrical cord. 
Besides the usual impressions, we may observe on the inside 
of the shell a line running obliquely from the print of the an- 
terior muscle, which is very long towards the nates. There is 
no flexure in the print of the mantle for the retractor muscle of 
the tube. (Tellina lactea.) 
Lucina, Brug. 
Separated lateral teeth, as in the cardia, cyclades, &c., 
13 
