CRINOIDEA AND ECHINOIDEA 



17 



these there are five species mentioned in Professor Nutting's 

 ''Narrative" which are not in the collection sent to me. One of 

 these {Dorocidaris hlakei) will be found discussed under 

 Cidaris abyssicola and another {Aspidodiadema spJ) under 

 Centr echinus antillarum. The others are inserted each in its 

 natural position in the list. 



Eucidaris tribuloides 



Cidarites tribuloides Lamarck, 1816. Anim. s. Vert., 3, p. 56. 

 Cidaris tribuloides A. Agassiz, 1872. Eev. Ech., p. 253; pi. Id and pi. 

 II, figs. 1-3. 



Eucidaris tribuloides Doderlein, 1887. Jap. Seeigel, p. 42. 



There is only a single specimen of this common West Indian 

 cidarid in the collection before me, but in the "Narrative," 

 the species is reported from the Tortugas (p. 132), where it 

 ''was found principally on the mud-flats just inside the reef," 

 and from Pourtales Plateau (p. 173). The specimen sent me is 

 labelled "Bahama Islands." It is a fine adult, 44 mm. in 

 diameter of test. 



Cidaris abyssicola 



Dorocidaris abyssicola A. Agassiz, 1869. Bull. M. C. Z., 1, p. 253. 

 Dorocidaris papillata A. Agassiz, 1872, Eev. Ech., p. 254 (in part) ; pi. 

 I, figs. 1-4. 



Cidaris abyssicola H. L. Clark, 1909, Ann. Mag. Nat. Hist. (8), 3. p. 88 



An excellent series of this cidarid is in the collection, but 

 most of the specimens are very young. They range in test- 

 diameter from 5.5 to 37 mm. Some of the smaller specimens 

 throw some light on the color of this species in life. The pri- 

 mary spines are pure white, except the very young ones near 

 the apical disk which, while still covered with the epidermis, 

 are brownish-red. The epidermis, while retained over the 

 whole spine, gives it a dull, smooth, opaque appearance, very 

 different from the mature spine. When the epidermis is first 

 shed the spines are quite rough with longitudinal series of mi- 

 nute sharp teeth, but with the passage of time these wear down 

 until in fully adult individuals the primary spines are nearly 

 or quite smooth. In one young specimen, the test and second- 



