275 

 TAPES AUREUS AND ITS ALLIES. 



By a. J. JUKES BROWNE, B.A., F.G.S. 



(Read before the Society, May loth, 1905). 



The attention of this Society has recently been called to some of the 

 species of Tapes occurring at Cette, in Southern France. Canon 

 Horsley brought back from there a large number of prettily-marked 

 specimens, and presented a good selection of them to the Manchester 

 Museum, at the same time communicating some notes on them which 

 were published in the April number o{ t\\Q Journal. 



I am induced to offer some remarks on these specimens and on 

 the species mentioned in his " Motes on Tapes," because the Medit- 

 terranean forms have passed under so many different names that I 

 think others beside myself must have found it difficult to decide 

 what names, both specific and varietal, should be adopted for the 

 specimens they happen to possess, more especially as- to those which 

 are related to Tapes aureus. 



By the courtesy of Dr. Hoyle, I have been able to examine all the 

 specimens from Cette in the Museum, and I find them to include 

 only two species. There are a number of typical T. deciissatus, with 

 one example of the variety intermedia B.D.D. The specimens referred 

 to T. aureus by Canon Horsley are unquestionably the form known 

 as Tapes texturatus (Lam.), with many of its colour- varieties, but 

 there is no specimen among them of typical Tapes aureus (Gmelin). 

 Nevertheless, his nomenclature can be justified, because some authors 

 consider T. texturatus to be only a well-marked Mediterranean variety 

 of T. aureus. 



There is no intermediate form between T. decussatus and T tex- 

 turatus, as Canon Horsley seems to have understood. The two 

 species are quite isolated from one another, and the name intermedia 

 applies only to a form which is intermediate between the Mediter- 

 ranean and British varieties of the species T. decussatus. 



Tapes decussatus Linn, need not detain us long. According to 

 Gmelin, Hanley, and Dautzenberg, the type specimens in the collec- 

 tion of Linneeus came from the Mediterranean, and consequently the 

 form there prevalent must be taken as the type. This differs from 

 that common on British and North French coasts in being more 

 regularly oval, less elevated posteriorly, more finely sculptured, and 

 more brightly coloured with variegated browns and greys. Our variety 

 is a more rectangular shell, higher from dorsal to ventral margin, thick 

 and coarsely sculptured with dominant concentric ribs, dull coloured 

 and seldom variegated ; this is the variety fusca of Gmelin. Messrs, 



