148 SVEN LOVEN, ON THE ECHINOIDEA UESCRIBED BY LINN/EUS. 



MENSURiE: diameter 74 mm., altitudo 54 mm. 



Two sub-adult specimens, one 50 mm. in diameter, 43 

 mm. in lieight, and with 5,.^ — 6 verrucse in the interradial 

 series, and another 59 mm. and 37 mm., and the same uum- 

 ber of verrueae, with tlie same flexuous zones deeply colou- 

 red, as is also the calyx, and with the same disposition of the 

 secondary verruculae in the scrobicular rings, are in every re- 

 spect similar, except that the ambnlacral areola presents but 

 two intermediary series of tertiary verruculae, or four, of which 

 the sutural two are verv minute and alternatino;, and that the 

 median areola of the interradia is still narrower, all in accor- 

 dance with what has been seen in the C. papillata. 



It has been remarked of this species, which it will be 

 convenient, notwithstanding the vagueness of the original de- 

 scription, to constitute as the Cidaris imperialis Lamck., that 

 it is hardly distinguishablc from the Phyllacanthus dubia of 

 Brandt'). This author adopted the genus Cidarites Lamarck, 

 which comprised the two >groups»: »Turbans» and» Diademas». 

 Of the former of these he made a »subgenus» called Phylla- 

 canthus, which is nothing else than the genus ten years be- 

 fore'-) named Cidaris by Gray. The species, indeterminable 

 from the description, which was drawn up not from nature, 

 the specimens having been löst, but from an unpublished 

 drawing, and for this verv reason provided with that ill-omi- 

 ned name, never ought to have been admitted. The form in 

 which Al. Agassiz with great doubts supposed to recognize 

 it^) seems to be a semi-adult specimen of the C. imperialis 

 Lamck., of which his figure 2 represents a young specimen, 

 with the interradial areola nearlv closed. A different form, 

 supposed by Australian naturalists to be the species had 

 in view by Brandt, has been sent me as a C. dubia by 

 Mr William Macleay of Sydney, and of the same species 

 another is in our old collection without a habitat. The for- 

 mer, 50 mm. in diameter and 36 mm. in height, with 6 or 

 6,5 verrucK in each interradial series, has a broadly open 

 interradial areola, equalling 0,i4 of the interradium at the am- 

 bitus, and four granules in a row between the scrobicidar circle 

 and the suture, Avhilc the two series of circles close only with 



') Prodromus descriptionis animalium al) H. Mertensio in orbia terra- 

 rum circumnavigatione observatorum, I, p. 67; 1835. 

 *) Annals of Philosophy, X, p. 426; 1825. 

 »} Revision, Pl. I/, fig. 6, 7, 



