24 



NATURAL HISTORY BULLETIN 



mary radicles are broken but the longest piece remaining 

 measures 57 mm. The smallest specimen is only 9 mm. in 

 diameter but the radioles are 29 mm. long. Of the 13 specimens, 

 11 have 4 anal plates, 1 has 3 and 1 has 5. Both of these latter 

 specimens are referred to by Professor Nutting in the ''Nar- 

 rative" (p. 83), where he speaks of this ''beautifully colored 

 species" which "made a pleasing display Mdth its brilliant 

 crimson and white spines." These individuals were taken on 

 the Pentacrinus ground off Havana but the same species was 

 found on the Pourtales Plateau and of these, it is said (p. 173) 

 they were "probably the most beautiful of the true sea- 

 urchins collected at this time, some specimens being considerably 

 larger than those secured off Havana. Not only are the long, 

 slender spines brilliantly colored with carmine and white or 

 orange, but the test itself is equally striking with its alternate 

 chocolate and orange zones, making it resemble, the gorgeously 

 colored balls in which children delight." 



Station 5. Cuba: off Havana, 140 fms. 1 specimen. 



Station 26. Florida: off Key West, 60 fms. 1 large specimen. 



No label, but apparently Cuba : off Havana, Pentacrinus 

 grounds, 110-200 fms. 11 specimens. 



Centrechinus antillamm 



Cidaris (Diadema) antillarum Philippi, 1845. Arch., Naturg., jhg. 11, 

 1, p. 355. 



Diadema setosum A. Agassiz, 1872. Rev. Ech., p. 274. {in part). 



It is of course to be regretted that the name Diadema, which 

 has been in use for many years for this most common and 

 easily recognized, and unfortunately most to-be-dreaded West 

 Indian sea-urchin, must be abandoned, but there can be no doubt 

 that Jackson (1912, Phylogeny Ech., p. 27) was absolutely right 

 in rejecting that preoccupied name and proposing the highly 

 appropriate and euphonious name, Centrechinus, in its stead. 

 Dr. Mortensen, whose opinion is entitled to more weight per- 

 haps than that of any other student of echini, disagrees with me 

 very decidedly on this point and refuses positively to give up 

 Diadema. He holds strongly to the view that Diadema is one of 

 those long-used names which should be arbitrarily maintained 



