90 PROCKKDINGS OF TIIK II A I.ACOLOGICAL SOCIKTi'. 



It must here be remarked that a genus PuUadra was first 

 proposed by Sowerby in 1826/ and it included most of the species 

 which Megerle and Lamarck had respectively allotted to their genera 

 Tapes and Venerupis. One can only suppose that Sowerby was 

 ignorant of Megerle's name, and did not agree with Lamarck's 

 separation of T^enerupis. Anyway, the name might have been 

 dropped as a synonym of Tapes if it had not been revived bv 

 subsequent authors for a section of that genus. The Messrs. Adams 

 used it in 1857 for a group of species which did not include V.piMastra, 

 a group which was in tlie same year called Paratapes by Eijmer. 

 Under the International llules a genus which contains a species 

 bearing the same name must take that species as a type; consequently 

 Fischer was right in giving Tapes pullastra as the typical example 

 of his section Fullasira, and Dr. Dall was right in definitely 

 indicating that species as the type of a sub-genus Pullastra. 



Lastly, with regard to the animals of the different forms of Tapes, 

 the differences which exist between them are not in very close, 

 correlation with the differences of the shells, and would not lead 

 us to the same generic grouping. If, for instance, we were to group 

 them in genera according to the partial union or the total separation 

 of the siphons, we should get a different classification from that based 

 on the characters of the shells. 



Thus Tapes lifferatus has long and nearly equal siphons which are 

 entirely separate from one another. In Paratapes euglf/ptus, for 

 a specimen of which I am indebted to Mr. Hirase of Kyoto, the 

 siplions are also quite free and separate from one another, but in 

 Polititapes (both rhomhoides and Icetus) the siphons are united for 

 about half their length. Again, in Japes decussatus. the type of 

 Amygdala, the siphons are free and sepai'ate, but in Tapes philippi- 

 narum (sent me by Mr. Hirase) they are united for three-quarters 

 of their length. 



The differences in the foot also show the same want of correlation. 

 In T'. litterahis the foot is long and tongue-shaped, but does not 

 possess a byssus, nor even a byssal groove, so far as I could see in 

 tlie spirit-preserved specimens sent me b}- Mr. J. Banfield of Dunk 

 Island, Queensland. In Paratapes the foot is very large, thick, 

 and elongated, and there is no trace of a groove at its base, 

 while in P. rJiomboides, and in the aureus group, the foot is rather 

 small, with a byssal groove, and castrensis is said to have a snuiU 

 byssus. Tapes decus.uitics has a small byssus, while T. philippi- 

 narum, or, at any rate, the specimen examined by me, has only 

 a groove ; both have a broad lanceolate foot, not thick, but rather 

 compressed. 



The distribution of these Tapesine genera at the ])resent day is 

 interesting, for the restricted section of Japes is essentially tropical, 

 being only found in the Indian Ocean ami in the western Pacific from 

 Japan to the northern parts of Australia. 



^ Genera of Shells, Zool. Journ., vol. iii, p. 134. 



