The Echinoderin Fauna of South Africa. 343 



* Ol'IIIOTIIKI.A IIIVIDUA. 



Von Martens, 1879. Sitzb. P.orlin Ges. Nat. Fr., p. -l!27, ligs. 1-i. 



Three of von Marten's cotypes are in the M. C. /. collection. They 

 were taken at Algoa Bay on alcyoiiarian coral. There is nothing 

 for me to add to the original description, but it may lie worth while 

 to note that these dry specimens have retained their pretty colour- 

 ation very well. The general effect is dull blue, of an indigo tint, 

 variegated with whitish; the deep blue lines across the outer ends 

 of the radial shields, and at intervals across the arm, are conspicuous. 



OPHIOCHITONIDAE. 



This small family was not previously known from South Africa 

 but the PIETER FAURE has detected three species, representing the 

 two most characteristic genera. They may be distinguished from 

 each other as follows : 



Key to the So nth African Species of Oph loch i ton idae. 



Supplementary plates present on each side of each upper arm -plate. 



Disk scales exceedingly numerous and minute, 150 200 or more per sq. mm. 

 near center of disk where they are scarcely distinguishable with a magnifying 

 glass. ...... Ophionereis dubia. 



Disk scales fine or rather coarse, 25 100 per sq. mm. at center of disk 



Ophionereis porrecta. 

 No supplementary plates present on the upper surface of arms 



Ophiochiton australis. 



OPHIONEREIS DUBIA. 



Ojihiolepis dubia Miiller and Troschel, 1842. Sys. Ast, p. 94. Savigny, 



1809. Descr. de 1'Egypte (Audouin): Rayonnes, pi. 1, figs. 3'-3 10 .' 

 Ophionereis dubia Lyman, 1865. Illus. Cat. M. C. Z., no. 1, p. 149. 



This species was not previously known from south of Zanzibar but 

 the PIETER FAURE collection shows it is a regular inhabitant of the 

 coast of Natal and eastern Cape Colony. None of the specimens are 

 full grown, the disk-diameters ranging from 2-5 to 6'5 mm. No two 

 are coloured alike; the disk is usually light, white or whitish, with 

 or without a dark spot or line, between or across the radial shields; 

 the arms are usually some light shade of brown or olive, with or 

 without indefinite whitish variegation, but in all cases with trans- 

 verse rings of brown at intervals of 3-10 (usually 4-6) segments; 

 these rings are usually very distinct on the dorsal surface but they 

 may be faint even there and wanting orally. Savigny's beautiful 



