254 DOROCIDARIS. 



is not correct; it is undoubtedly a Pacific species. The original of Lamarck's 

 Oidarites metularia is from the Isle de France, there are also in the Jardin 

 des Plantes specimens from the Red Sea ; it has an extensive range, occurs 

 as far as the Sandwich Islands, is quite common in the East Indian Archi- 

 pelago. The O. metularia Lam. is also identical with the species which 

 I named Gymnocidaris minor, in the Museum Bulletin (1863). Not having, 

 at the time, had the opportunity of examining series of different ages, I find 

 that the differences which had been considered as specific are simply differ- 

 ent stages of growth. 



In this species of Cidaris, as in genus Cidaris usually, the difference be- 

 tween old and young stages is almost entirely limited to the proportionally 

 larger size of the spines {PL II c .f. l-l) and the more prominent serrations 

 (recalling Salenia). The abactinal system early assumes the character of 

 the adult ; in fact, witli the exception of the smaller number of coronal and 

 buccal plates, the above differences in the spines arc the only important 

 changes undergone in this genus. 



Littoral to 110 fathoms. 



(CIDARIS.) DOROCIDARIS. 

 Dorocidaris A AgabS. 1869. Bull. M. C. Z , I. et al. 



This subgenus differs from Cidaris proper by its narrow median ambula- 

 cra; in interambulacral area, the smaller number of primary tubercles, with 



a deep sunken scrobicular area, the scrobicular circle formed by close granula- 

 tion, leaves the median interambulacral space more or less sunken and bare. 

 The abactinal area is large, does not differ essentially from Cidaris. The 

 spines of this subgenus arc long, surpassing the diameter of the test, often 

 twice as long as diameter; fluted, or with pointed granulations arranged in 

 longitudinal ridges or forming disconnected lamellae. Poriferous zone nar- 

 row, undulating with disconnected pores. 



Dorocidaris papillata 



Cidaris papillata L,kske, 177S. Klein. Add. 

 ! Dorocidaris papillata A. Ag. 18G9. Bull. M. C. '/.., I. 



PI I; PL IT./. 13-15 ; PL P. ; PL TP.f. 1-lS; PL IP.f. 1-5. 



I had, in the Preliminary Report, distinguished the specimens from Florida 



from Cidaris papillata as Dorocidaris abyssicola. An examination of a fine 



series of Cidaris papillata collected on the west coast of Norway by Dr. Sais. 



in the Shetland Islands, and in sundry localities extending from Cape Wrath, 



