272 Dr. G. J. Hinde on Hystricrinus, Hinde^ versus 



way to reflect upon this gentleman, who, in a letter to me of 

 the 13th May last, acknowledging the receipt of my paper on 

 Hystricrinus, says : — " I agree with you in the impropriety 

 of my generic name [i. e. Arthroacantha] and shall adopt 

 yours. It was a provoking accident which caused me to 

 overlook that single page of names applied to Rotatoria in 

 Marshall's index." 



As Messrs. Wachsmuth and Springer recognize the rules of 

 zoological nomenclature of the British Association Committee, 

 it may be desirable to give quotations from the particular one 

 bearing on this subject* : — 



" It being essential to the binomial method to indicate 

 objects in natural history by means of two loords only, 

 without the aid of any further designation, it follows that a 

 generic name should only have one meaning — in other words 

 that two genera should never bear the same name. . . . When 

 these cases occur the later of the two duplicate names should 

 be cancelled and a new term, or the earliest synonym, if there 

 be any, substituted. ... It is, we conceive, the bounden duty 

 of an author, when naming a new genus, to ascertain by 

 careful search that the name which he proposes to employ 

 has not been previously adopted in other departments of 

 natural history. By neglecting this precaution he is liable 

 to have the name altered and his authority superseded by the 

 first subsequent author who may detect the oversight. . . . 

 We submit therefore that a name should be changed which 

 has before been proposed for some other genus in zoology or 

 botany, or for some other species in the same genus, when 

 still retained for such genus or species." 



Applying the above rule to the present case, we have the 

 names : — 



ArtJtracmithus, Schmarda, 1854. From updpov^ joii't) 

 and IxKarda^ spine, for a genus of Rotatoria, character- 

 ized by movable spines, which serve as oars to the 

 animal. 



Arthroacantha^ Williams, 1883. Also from afjdpor^ 

 joint, and uKuida^ spine, for a genus of Crinoids cha- 

 racterized by movable spines. 



It is very evident that both these generic terms have one 

 and the same meaning, and this fact would, according to the 

 rule quoted, require that the later one should be changed. 

 If we turn now to the proper construction of these words, there 

 is no doubt that, in accordance with the regular method of 

 forming compound Greek words, tSchmarda's term is correct, 

 and that Williams and Wachsmuth and Springer are ortho- 

 graphically in error in retaining the " o " in Arthroacantha, 

 * Loc. cit. p. 34. 



