348 Annals of the South African Museum. 



Tentacle-scales 2, often 1 distally. 



Colour variegated; more or lees whitish on under side of arms; arms 

 5-8 times disk-diameter . . Ophiocoma scolopendrina. 



Colour very dark, nearly or quite black; no light colour anywhere; arms 

 short, 4 5 times disk-diameter . . . Ophiocoma erinaceus. 



Tentacle-scales 1, sometimes 2 on the first few basal joints. 



Colour very dark as in erinaceus . . Ophiocoma schoenleinii. 



Colour more or less light and variegated . . Ophiocoma valenciae. 



Disk free from granules, but usually with a few scattered, blunt spines 



Ophiornastix venosa. 



OPHIOCOMA SCOLOPENDRINA. 



Ojthiura scolopendrina Lamarck, 1816. Anim. s. Vert., vol. 2, p. 544. 



Ophiocoma scolopendrina Midler and Troschel, 1842. Syst. Ast., p. 101. 



H. L. Clark, 1915. Mem. M. C. Z., vol. 25, pi. 14, ligs. 10, 11. 



This common and wide-ranging brittle-star is known from Mo- 

 zambique to Tahiti and from Torres Strait to southern Japan. As 

 stated above, I do not accept the record of its occurrence at the 

 Cape of Good Hope. Matsumoto, in his recent admirable monograph 

 on Japanese ophiurans (1917, Jour. Coll. Sci. Imp. Univ. Tokyo, 

 vol. 38, art. 2) considers the two following species as merely varieties 

 of this one. While he may be right in this, I prefer not to discuss 

 the matter here, as a revision of the family Ophiocomidae has appear- 

 red in my recently published (1921) account of the Echinoderms of 

 Torres Strait. There is no difficulty in distinguishing the three forms 

 from each other. A specimen in the South African Museum collection, 

 taken at Mozambique, in November, 1912, by K. H. Barnard, is 

 undoubtedly sco lopendrina. 



* OPHIOCOMA ERINACEUS. 



Miiller and Troschel, 1842. Syst. Ast., p. 98. H. L. Clark, 1915. Mem. 

 M. C. Z., vol. 25, pi. 15, figs. 5, 6. 



This species has been the source of much dispute for there are 

 many museum specimens which are intermediate between typical 

 erinaceus and scolopendrina. After studying the two forms alive in 

 Torres Strait, I became convinced that, at least in that region, they 

 do not interbreed, or even mingle. I therefore consider them distinct 

 species. The occurrence of erinaceus at Mozambique seems to be 

 established. 



