JUKES-BROWNE : NOMENCLATURE OF VENERID^. 37 



siphons are short and iiiiited, tlie foot hatchet-shaped and not 

 byssiferous ", while under Chione he states that the siphons are 

 shoH and separate ; but if this latter statement is meant to apply 

 to all sections of Chione, as seems to be intended, then it is erroneous, 

 for most of the European species have their siphons more or less 

 united. The common C. gallina and the British variety C. striaiida 

 have siphons united for more than half their lenjitli ; in C. faseiata 

 they are united for about half the len<?th, and of C. {Tinioclea) ovafa 

 Forbes & Hanley say that "the siphons are united nearly to the 

 extremities, but they diverj^^e at the ends". The length, of the 

 siplions varies in different species and sections of Chione. 



Consequently the omts prohandi rests upon Dr. Dall, not upon 

 me. If he still persists in his opinion he must justify it by a full 

 and complete comparison, stating clearly the characters in which 

 he thinks Protothaca (both shell and animal) diifers from Chione., 

 and those in which, it resembles Tapes. In my opinion the hinge 

 is that of Chione and not that of Tapes. The only point, so far as 

 I can see, in which Protothaca resembles the latter more than the 

 former is in the pallial sinus, wliicli is deeper and more rounded 

 at the extremity than in typical Chione, but some species of the 

 Tiinoclea section, such as T. yallinula and T. higopus, have a similar 

 rounded sinus. 



Dr. Dall makes another extraordinary statement when he writes that 

 because genera proposed with only one species are monotypical, "on 

 this basis I have regarded the species cited in Lamarck's Prodrome 

 (if 1799 as typical of tlie genera accepted or proposed by him in 

 that publication." The italics are mine, for there is all the difference 

 in the world between proposing a new genus and accepting an old 

 one ! The example given by Lamarck for his genus Meretrix is of 

 course to be taken as the type, but that given for the Linnean genus 

 Venus is not necessarily the type, because he did not specify it as 

 such. Hence it is untrue to say that I have objected to " the 

 acceptation of the monotypical genus". Dr. Dall must have read 

 my paper very carelessly, or he would not have failed to notice 

 tbiit I began by drawing attention to the recent decision of the 

 International Committee on Zoological Nomenclature to the effect 

 that "mention of a species as an illustration or example of a genus 

 does not constitute a selection of a type". 



I do maintain that Gafrarium (as adopted by the Adams brothers) 

 is monotypical, because the live supposed species listed by the Adams 

 are now acknowledged to be only varieties of one species, and I quoted 

 Dr. Dall's own statement to that effect, viz. that "the type and 

 sole recent species is Venus Jiinhriata, Linn." 



If Holten's names are to be accepted Corhis must give way to 

 Gafrarium, but 1 trust that the rigid application of the priority rule 

 will not be enforced. I entirely approve of the proposal that the 

 International Committee should publish an official list of generic 

 names, and that they should be authorized to establisli certain names 

 which have been in general use for half a century or more on a 

 permanent basis by exempting them from change. I would, in fact, 



