GASTRANA. 369 



in the newer tertiary strata of the south of Italy. This 

 species being common in some parts of the west of Ire- 

 land which have been often explored by many of our 

 best zoologists, it is surprising that the animal has not 

 been noticed by any writer on the British or Irish Mol- 

 lusca, and that it should have devolved on a German 

 conchologist to examine it on the distant shores of 

 Sicily, and on a French savant to investigate its ana- 

 tomy in North Africa. Their descriptions, however, 

 differ from that of Poli, as well as among themselves. 

 According to Philippi the siphonal orifices are not cir- 

 rous ; the characters of the animal which I have quoted 

 from Deshayes give the number of cirri which surround 

 the aperture of each tube ; while Poli states that the 

 cirri encircling the branchial tube are scarcely percepti- 

 ble, even by the aid of a lens, and that the mouth of the 

 other tube is plain. The lesser tooth in the left valve 

 is thrown into the shade by its huge companion, and 

 the genus is represented by authors as having only one 

 tooth in that valve. Montagu says that his Tellina 

 polygona has, " besides the very large, triangular, bifid 

 tooth, an approximate small one, that might easily be 

 passed unnoticed." I believe that shell was only a 

 half- grown and distorted G. fragilis ; I have one exactly 

 answering to the particulars and figure given in the 

 ' Testacea Britannica.' The young are more oval, and 

 not so inequilateral. A specimen in my collection con- 

 tains a small incipient pearl close to the posterior scar. 

 The regularity of sculpture varies in individuals from 

 different localities. 



It is the Tellina striatula of Olivi, T. jugosa of Brown, 

 Petricola lamellosa and P. ochroleuca of Lamarck, and 

 (in its younger or immature state) his Psammotaa 

 tarentina. 



R 5 



