ECHINOIDEA. I. jg 



groiipera naturellement un assez grand nonibre d'especes vivantes et fossiles et nie parait utile a 

 conserver. The advantage of such a genus >, however, seems to nie to be ratlier iUusory; with the 

 limitation given b>' de Loriol Rhabdocidaris becomes still more heterogeneous than Phyllacanthiis, 

 as it is limited by Agassiz in Revision). As the genus has originally only been used of fossil 

 species, it is quite impossible to decide whether some of the recent forms really belong to it; b)- the 

 tests and the spines alone the genera cannot at present be recognised with certainty, and no pedicel- 

 lariae of fossil species are known. Accordingly the name of Rliahdocidaris is not to be used for any 

 recent Cidarid. 



On the other hand the other species with terminal opening on the globiferous pedicellarise 

 and limb on the stalk seem to form a natural group; the shortness or length of the limb can 

 scarcely be used as a character for the subdivision of the group. Pos.sibh- C. affinis and Rcini (and 

 perhaps paiiaiiiriisis) will jirove to form a special group — their spines seem to differ somewhat from 

 the other mentioned species; but this can only be decided by more thorough examinations. For the 

 present all these species: Cidaris affinis^ Rcini^ (panainciisis?)^ tribuloidcx, galapagensis, mehilaria, Thoii- 

 arsii^ vcrticillata , and baciilosa^) must form one genus, which must keep the old name of Cidaris^ 

 Linne's 'iEchhiiis Cidaris^^ as has been proved by Loven (252), being Cidaris baculosa Lanik. The 

 name oiEuctdaris Pomel, which has of late often been used for species of this group, cannot correctly 

 be used. Pomel (324) enumerates as types of this genus some fos.sil forms {iiioricri etc.) from the trias, 

 and trois especes vivantes >, but he does not mention which species he means, and the fact is here, 

 as in Rhabdocidaris^ that it is quite impossible to decide whether any of the recent species belong to 

 the same genus as the mentioned fossil ones. 



Besides the species mentioned here, Doderlein still enumerates ■ LeiocidarisK annulifcra Lam. 

 as belonging to those species, the globiferous pedicellarise of which have terminal opening and limb 

 on the stalk ; here C. anmdifera is referred to the genus Stcphanocidaris which has a quite different 

 form of pedicellarise (see above) — a contradiction which can only have its origin from a difference 

 in the interpretation of the species C. annulifcra Lamk. This species together with C. baculosa Lam. 

 have caused and still cause many difficulties to the systematists. Lamarck-') in his diagnosis of 

 C.ai/nnlifera says: spinis majoribus longis, tereti-subulatis, asperulatis, albo purpureoque annulatis», 

 and in his diagnosis of C. baculosa: spinis majoribus subteretibus, tuberculato-asperis, apice trnncatis, 

 collo guttatis ; according to this Agassiz (Revision of Pxhiui p. 389) states as the only certain 

 character of the highly varying C. baculosa the spotted base of the shaft of the spine below the 

 milled ring, which is of a light reddish or reddish-yellow ground-color, with deep violet .spots marked 

 extremely distinctly upon the fine longitudinal striatiou). Loriol (243) later describes and figures a 

 Cidarid by the name oi C.aiinnlifera'L,&mk.] he has had a radiole of the type-specimen of this species 

 for comparison, and has found it completely corresponding to those of the specimen described by him. 

 These spines have leur base couverte sur une longueur plus on moins grande de petites taches 

 pourpres, formant des lignes et entremelees de petits points^ — the character especially particular of 

 C. baculosa ! Thus, somehow or other, an error must have slipped in, and I think it most likeh- that 



') If C. pisfillaris Lamk. be a good species, it must also be referred here. 

 -) Histoire naturelle des aniniaux sans vertebres. II. Ed. 1S40. T. III. p. 5S0. 



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