288 Miscellaiieoua. 



the subject of this paper. But I do deny that Brandt made C. trihu- 

 loides genotype of a restricted Cidaris. 



If the rule of first reviser is to be applied, we must turn to a 

 paper quoted by many, but entirely overlooked by Prof. Clark. 

 J. E. Gray (1825, Ann. Philos, xxvi. p. 420) fixed the genotype as 

 C. imperialis Lam., still further defining that species by a reference 

 to Klein, t. vii. f. A. This, it will be remembered, was the type of 

 Leske's Var. I. major ; it was also the first species mentioned by 

 Lamarck; therefore on both counts Gray was only following the 

 dictates of common-sense in taking it as the genotype. Under the 

 rules of nomenclature, however, this choice can be justified only by 

 reinstating papillata as the trivial name of this species, leaving 

 hystrix to Leske's Var. III. This conclusion would, of course, cut 

 out PhyllacantJms, a much older genus than Dorocidaris. 



This line of argument need not, however, be pursued further. 

 Cidaris imperialis, by whatever name it be callel, is excluded by 

 the previous application of the tautonomy rule. The genotype of 

 Cidaris by that rule is C. papillata = Echinus cidaris. 



Among the results, " unfortunate " or otherwise, of this rule are 

 the retention of PhyUacaiithus, tlie suppression of the name Doro- 

 cidaris, and its replacement by Cidaris transferred from the section 

 to which it is applied by Clark (viz. C. metularia, C. tnbuloides, 

 C. ihoiiarsi), as well as from that to which it is applied by Mortensen 

 (viz. the same three species -f- 1'. cffi'iis, C reini, and C. bacidosa, of 

 which the two former are referred by Clark to Tretocidaris Morten- 

 sen, and the last to PhyllucaatJius). For a genus including all 

 these species and others Doederlein (1906) has revived the name 

 Cidarites Lamarck, without fixing on a genotype. In Clark's 

 protest against this resurrection I heartil)' join, for the simple 

 reason that Leske himself used Cidarites and Cidaris indifferently, 

 applying the former name to C. excavntas, C. coronalis, C. corollaris, 

 C. circinuatus, and C. ovarius merely because they were fossils. 

 As Clark says, Cidarites, in Lamarck's sense, " is clearly a substitute 

 for, and synonym of, Cidaris." 



If a generic name be required for this section, one is already 

 provided in Gymnocidaris A. Agassiz, 1863, with genotype Cidaris 

 metidaria. 



The main results of tliis enquiry may be summarized thus : — 

 Cidaris Leske (synn. Cidarites Lam., Dorocidaris A. Ag.). 

 Genotype, C.papillata Leske, restr. (synn. Echinus cidaris 

 Linn., 1758, and Cidarites hystrix Lam.). 



Gymnocidaeis a. Ag. (synn. Cidarites restr. Doederlein, 

 Cidaris restr. Clark). 



Genotype, O. metularia (Lam.). 

 Phyllacanthxts Brandt (syn. Cidaris restr. Gray). 



Genotype, P. imperialis (Lam.). 



I express no opinion as to the validity or extent of these generic 

 divisions. 



