98 CONTRIBTJTIONS TO CANADIAN PALEONTOLOGY. 



Middle Devonian of Arkona, Ontario, and the locality, as well as the 

 descrijjtion and figures, leave little room for doubt that Dr. Hinde's 

 specimens are both si^ecifically and geiierically identical with those 

 whose nomenclature is now being discussed. In this and in a subse- 

 quent jjaper Dr. Hinde claims that Professor Williams' genus Arthroa- 

 cantha cannot be retained, because "the name A?-thracanthus was 

 employed by Schmarda in 185-1 for a genus of Eotatoria,'' and tjiat the 

 sjjecies Arthroacaiitha panctohrdchiata must alsn be rejected, because it 

 was never propierlj' described. 



But to the first of these objections it may bo answered that, although 

 from a purist's standpoint, the o in Arthroacaiitha may be superfluous, 

 3'et the difference in the terminations of the two words in question is 

 quite suflicient to admit of the use of both. Generic terms which ditfer 

 only in this respect, such as, for example. Picas, a woodpecker, and 

 Pica, a magpie — Cyprinus, a carp), and Ci/prina, a mollusk — and many 

 such instances could be cited, are in universal use among biologists at 

 the present day, with no inconvenience resulting therefrom. In reply 

 to Dr. Hinde's second contention, viz., that the A. punctohrachiata has 

 never been ptroperlj' described, the whole of the original descrijition of 

 that sjjecies has already been (juoted, so that the reader, on this point, 

 can form his own O2)inion. In the writer's judgment, however, the dis- 

 tinctive charactei's given by Prof. Williams, though largel}- negative 

 and unaccompanied with any figures, are yet sufficiently explicit to 

 allow of the recognition of the species, and if this be the case, the 

 laws of nomenclature would seem to require that his name should be 

 adopjted. 



DOLATOCRINUS LIRATDS, Hall. 



Cacahocrimis llriUas, Hall. 18G2. Fifteenth Rep. N. York St. Cab, Nat. Hist, p. 



139. 

 Dolutocrlnu!: lirati.ix, S. A. Miller. 1877. Cat. Am, Pal. Foss. p. 77. 



" " Wachsmuth and Springer. 1881. Rev. PalKOcrinoidea, pt. 2, 



p. 126. 



Bartl^t's Mills, near Arkona, Eev. J. M. Goodwillie, 1S82 : one 

 good specimen, which a]jpears to belong to this species, although, as 

 pointed out hy Mr. Wachsmuth, it has only 1x2 secondaiy radials 

 (brachials, Hall) while the type of D. liratm is said to have 2x2. 

 The generic and specific characters of this specimen and of the beau- 

 tiful example of Ollacrinus spinigerus collected by the Eev. Hector 

 Currie, were first recognized by Mr. H. M. Ami. 



