A Remarkable New Brittle Star 



HUBERT LYMAN CLARK 



Ophiocryptus gen. nov. 



6(l)L<;=snake (a very common prefix for genera of brittle stars) 



KpvTTTO'i^^c once ale d; in reference to the concealment 



of the disk scales and arm plates by granules.) 



Disk covered with rather swollen plates, which are either com- 

 pletely concealed by coarse granules or are bare at the middle only. 

 Upper surface of arm more or less covered, with a coat of granules. 

 Oral shields (except madreporite) , adoral plates and oral plates, 

 completely concealed by a coat of granules continuous with that 

 which covers the interbrachial areas. Arm spines short and thick. 

 Genital slits, four in each interbrachial area. Tentacle scales 2, well 

 developed. 



Type-species: Ophiocryptus maculosiis sp. nov. (see below). 

 This genus is nearly related to Ophioncus, described by Ives 

 (1889) from the "West Coast of North America." The complete 

 concealment of the mouth plates by granules and the large amount 

 of granulation on the arms are important differences, however, and 

 prevent assigning the present species to Ives' genus. Moreover the 

 bareness of certain disk-plates at their center while the radial shields 

 are entirely concealed is an odd feature. Koehler has recently de- 

 scribed and figured (1914, Bulletin 84, U. S. Nat. Mus., p. 8; pi. 

 2, figs. 1,2) an Interesting little ophiodermatid from the Bahamas, 

 which he considers a young Ophioderma. His admirable photo- 

 graphs show however that it is very close to the species I am here 

 describing, but differs in having longer arms and bare radial shields. 

 In the last particular and in the uniform granulation of the disk. It 

 resembles Ophioncus. As It has six arm spines I suggest that it may 

 well be called Ophiocryptus hexacanthus. The type is U. S. Nat. 

 Mus. Ac. No. 41471, and is from Green Cay, Bahamas. 



Ophiocryptus maculosus sp. nov. {m aciil o sus '= s^otttd) 

 Disk 6 mm. In diameter; arms 9 mm. long, flattened, especially 

 near tip, of 17 visible joints. Disk evidently covered by rather 



