JUKES BROWNE : TAPES AUREUS AND ITS ALLIES. 279 



described a Venus fiorida. It must l)e remembered, therefore, 

 that the name Tapes catetiifer stands for T. Icetus (PoH) and T. 

 floridiis (Lam.). 



The name texturatus has also been considered by Hanley and 

 others of doubtful application, because Lamarck gave for the locality 

 of his type the " Indian Ocean." On the other hand, he cites 

 Chemnitz, " Conch. Cab.," fig. 443, as an illustration of the species 

 texturatus, and this figure is stated to be clearly meant for the Medi- 

 terranean species. Nearly all subsequent authors have assumed that 

 the name really belongs to the Mediterranean shell, and M. Dautzen- 

 berg informs me that he has examined Lamarck's types at Geneva, 

 and has satisfied himself that the three specimens labelled " Venus 

 texturata " in Lamarck's handwriting are specimens of this shell ; so 

 that there seems to be no doubt about the proper application of the 

 name. 



There remains only the question of the value of the groups to 

 which these and the other names are attached. M. Locard has 

 recognised no fewer than twenty-six different species of Tapes on the 

 French coast ; M. Dautzenberg, on the other hand, thinks that it is 

 better "to group under one name all forms between which it is easy 

 to find many intermediate links" {op. cit., p. 396). English concholo- 

 gists will quite agree with him that mere variations of outline and 

 colour are not of specific importance in the genus Tapes, and that we 

 must have regard to the " ensemble des caracteres." It is the old 

 story of "splitting" and "lumping," and the question resolves itself 

 into one of scientific proportion and convenience. I strongly dissent 

 from minute splitting, but I am inclined to think that the principle of 

 combining all the forms which can be connected by intermediate 

 variations may be carried so far as to become inconvenient. Bino- 

 mial nomenclature is itself a matter of convenience, and if we group 

 too much it becomes trinomial or quadrinomial, for well marked local 

 varieties must have a name. 



I think the present case is eminently one in which the via media is 

 the most satisfactory and convenient course. I should contend that 

 the mere fact of two polymorphic specific groups being connected by 

 some local intermediate forms is not sufficient to prevent our regard- 

 ing both of them as species. Modern naturalists believe that all 

 closely-allied forms have been developed from one common ancestor. 

 In this process of development some of the mutations which formed 

 links between some of the persisting varieties may also have persisted, 

 others may have died out ; in the one case we have species that are 

 more or less linked to one another by intermediate varieties, in the 

 other we have isolated species ; but the latter may not differ more 



