ECHINOIDEA. I. 



19 



groiipera natiirellement 1111 assez grand nombre d'espéces vivantes et fossiles et nie parait utile å 

 conserver>. The advantage of such a -genus , liowever, seems to me to be rather illusor}'; with the 

 limitation given by de L or i ol Rhabdocidaris becomes still more heterogeneons than Pliyllacanthus^ 

 as it is limited by Agassiz in (Revision*. As the genus has originally only been nsed of fossil 

 species, it is qiiite impossible to decide whether some of the recent forms really belong to it; by the 

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

 lariæ of fossil species are known. Accordingly the name of Rhabdocidaris is not to be nsed for any 

 recent Cidarid. 



On the other hånd the other species with terminal opening on the globiferous pedicellariæ 

 and limb on the stalk seem to form a natnral gronp; the shortness or length of the limb can 

 scarcely be used as a character for the subdivision of the group. Possibly C. afjiiiis and Rci)ii (and 

 perhaps panamensis) will prove 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 s\)&c\es: Cidaris a/fiiiis^Rciiii, { panamensis ?)^ tribuloidcs^ galapagcusis^ iiicfiilaria^ T/ioit,- 

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

 Linné's 'iEchinus Cidaris^, as has been proved by Loven (252), being Cidaris baciilosa Lamk. The 

 name of Eiicidaris Pomel, which has of late often been used for species of this groui), cannot correctly 

 be used. Pomel (324) enumerates as types of this genus some fossil forms [?uQricri etc.) from the trias, 

 and «trois espéces vivantes», but he does not mention which species he means, and the faet is liere, 

 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 liere, Doderlein still enumerates Lciocidaris^ annnlifera Lam. 

 as belonging to tliose species, the globiferous pedicellariæ of which have terminal opening and limb 

 on the stalk ; liere C. annulifera is referred to the genus StipJiaiiocidaris which has a quite different 

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

 in the interpretation of the species C. annulifera Lamk. This species together with C. baciilosa Lam. 

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

 C. annulifera says: vspinis majoribus longis, tereti-subulatis, asperulatis, albo purpureoque annulatis>, 

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

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

 character of the highly varying C. baculosa -the spotted base of the shaft of the .spine belbw 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 striation->. Loriol (243) later describes and figures a 

 Cidarid by the name oiC.annulifcra\^z.\\\V.\ he has had a radiole of the type-specimen of this .species 

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

 These spines have deur base couverte sur une longueur plus ou moins grande de petites taches 

 pourpres, formant des lignes et entremélées 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 likely that 



I) If C.pistillayis Lamk. be a good species, it must also be referred here. 



=) Histoire naturelle des animaux sans vertébres. II. Ed. 1840. T. III. p. 3S0. 



