CRINOIDEA AND ECHINOIDEA 



25 



by means of a list of nomina conservanda, adopted by interna- 

 tional agreement. To this I should make no objection whatever 

 and if it ever is done, I will cheerfully take up Diadema again. 

 Meanwhile it seems to me that Centrechinus is the only correct 

 name for this genus of long-spined, poisonous black sea-urchins. 



Mr. Agassiz did not distinguish between the species of the 

 East and West Indies, in the Revision, but later (1908, Mem. 

 M. C. Z., 34 p. 112) he came to agree with Mortensen in recog- 

 nizing half a dozen species, and in restoring Philippi's name to 

 that of the West Indies. 



This is unquestionably the most conspicuous and generally 

 known of the West Indian sea-urchins but oddly enough it has 

 never been adequately figured. The photographs of Diadema 

 setosum given in the Revision are not taken from West Indian 

 specimens. The little drawing (fig. 1) on the plate opposite p. 

 224 in the "Narrative", and labelled ' ^ Aspidodiadema sp." 

 gives as good an idea of the appearance of this sea-urchin in 

 life as any figure I can find. This figure is a life-size drawing of 

 a young Centrechinus ; and except for the banded spines would, 

 if magnified three or four times, represent the adult equally well. 

 It is an interesting fact that the young of this species always 

 have the spines prettily banded with purplish-violet and white. 

 They thus look very unlike the adults and it is not strange that 

 they are often mistaken for a different species. In the "Nar- 

 rative" (pp. 83, 223) these pretty little long-spined urchins 

 are referred to as Aspidodiadema of uncertain species. The 

 specimens in the collection sent me are also labelled Aspido- 

 diadema. These young specimens of Centrechinus are referred 

 to in the "Narrative" as occurring at the Pentacrinus ground 

 off Havana (p. 83) and near Little Cat Island, Bahamas (p. 

 223). Adult examples were found at Egg Island, Bahamas 

 (p. 45), the Tortugas, Florida (p. 132) and at Spanish Wells, 

 Eleuthera Island, Bahamas (pp. 202, 213). Professor Nut- 

 ting's field notes on the very painful stinging powers of the 

 spines (p. 132) and of the possible use of the jaws in rock- 

 boring (p. 213) are of great interest and value but are too ex- 

 tended to warrant repetition here. The specimens of Centre- 

 chinus in the Iowa collection are as follows : 



