.'!:(> Annals of the. South African Mnxeinn. 



Upper and under arm-plates distinct; no radiating black lines on disk. 



Upper surface of arms marked with narrow transverse lines of 



deep red . . . Ophiothrix poecilodisca. 



Upper surface of arms, at least near tip, with a narrow median 



stripe made up of three white lines separated from each other 



by distinct black ones . Ophiothrix trilineata. 



Disk plates flat, smoothly covered by a uniform coat of granules ; radial 



shields bare and very large . . . Ophiocnemis marmorata. 



Under arm-plates wanting or apparently so. 



Side arm-plates projecting as spine-bearing ridges occupying the whole 

 height of the arm or nearly so; upper surface of arms in adults (except 

 distally) covered by a coat of granules and not showing any upper arm- 

 plates . ... Ophiopsammium nudum. 

 Side arm-plates low, squarish, projecting as wing-like plates on lower 

 half of arm; upper surface of arms with irregular granules among which 

 the upper arm-plates can often be distinguished Ophiothela dividua. 



OPHIOTHRIX ARISTULATA. 

 Lyman, 1879. Bull. M. C. Z., vol. 6, p. 50 ; pi. XV, figs. 421424. 



In Mr. Lyman's description, he says the arm-spines are "scarcely 

 tapering' 1 and "slightly flattened". If this were so, it would be 

 exceedingly difficult to distinguish this species from triylochis and 

 fragilis (see below, under fragilis) but the many specimens I have 

 seen from South Africa, the East Indies and Australia, including 

 two of Lyman's cotypes from the Agulhas Bank, have tapering, 

 acuminate spines which are seldom appreciably flattened. They 

 show some diversity in length, relative thickness and thorniness but 

 they are seldom stout and often very thorny. Bell (1905, Mar. Inv. 

 S. Afr., vol. 3, p. 258) records this species from two stations, one 

 in 35 fms. and one in 22 fins. Specimens of Ophiothrix from the 

 latter station are before me and are here listed as triglochis, the 

 common South African species, which Bell records from only one 

 station. As aristtilata is normally a deep water species, I suspect 

 all of Bell's specimens were triglochis. 



The PIETER FAURE collection contains only seven specimens of 

 this line species. They range in disk diameter from 6 to 14 mm. 

 and all are nearly white, with more or less of a pinkish tinge still 

 left on the arms; on the upper arm plates, there are faint indica- 

 tions of a more or less broken median longitudinal, white stripe. 



P.F. 2529. Lion's Head, N. 63 E., 34 miles, 154 fms. Blk. spcs. 

 3 specimens; adult. 



P.F. 2798. Vasco de Gama Peak N. 71 E, 18 miles, 230 fms. 

 Stn. 2 specimens; adult. 



