338 Annals of the South African Museum. 



The largest specimen is 13 mm. across the disk. In colour, the 

 diversity is very great, ranging from almost pure white (dry spe- 

 cimens) to deep, dull indigo, on the disk. The arms range from 

 white to pink, dull red or various shades of brown; often there are 

 indications of alternating red and blue bands; sometimes there is a 

 distinct median white stripe and usually the distal tip of the upper 

 arm-plates is white: not uncommonly the whole distal margin of 

 each plate is whitish. The variation in the disk covering is nearly 

 as great as in the coloration. Typically, the whole upper surface 

 of the disk including the radial shields is covered by low, thorny 

 stumps as shown in Koehler's fig. 41, but the stumps themselves 

 show no little diversity, for they may be low and crowned with 

 short thorns (see Koehler's fig. 43) or slender and more cylindrical 

 (Koehler's fig. 44) or they may, whether low or high, be crowned 

 with three long, slender spinelets; all sorts of intergradations be- 

 tween the extremes occur. Moreover in some specimens from False 

 Bay, we find among the stumps, disk spinelets over a millimeter 

 long and more or less thorny; in the largest specimen, these are 

 so numerous as to replace most of the stumps and the radial shields 

 are bare. This individual, if by itself and labelled "Saldanha Bay", 

 would probably be considered frag His. Compared directly with 

 Saldanha Bay specimens however, several differences are obvious; 

 the radial shields are much smaller in triylochis, the disk spines, 

 much less thorny, the upper arm-plates wider and smoother and 

 the under arm-plates shorter and wider and more widely separated. 

 These differences hold so well in all the material at hand that I 

 feel justified in not uniting the two species as one. 



I am inclined to think 0. roseocoerulans Grube of St. Helena is 

 not to be separated from triylochis but until more is known of the 

 colour varieties of the Cape species, they may be kept apart. I have 

 no doubt however that the specimens from False Bay, identified 

 by Bell as roseocoerulans (op. cit. p. 258) are better referred to 

 triglochis. 



The PIETER FAURE collected triglochis at the following points: 



P.F. 106 A. Between Cape St. Blaize and Mossel Bay, 4 fms. 

 S. 2 specimens; young. 



P.F. 507. Algoa Bay, 33 58' S. 25 51' E, 25 fms. R., blk. 

 spcs. 1 specimen ; adult. 



P.F. 590. Algoa Bay, 33 50' S. x 25 54' E., depth and bottom 

 not recorded. 1 specimen ; young. 



P.F. 769. Near East London, 32 52' S. x 28M2'E., depth and 

 bottom not recorded. 30 specimens; adult. 



