322 Annals of the South African Museum. 



iii 'ins, the bareness of the sides and lower surface of disk, the big 

 upper arui-plates and the covering of the disk itself make a com- 

 bination of characters which are quite distinctive. The species is 

 evidently not a rare one on the southeastern coast of Cape Colony 

 but does not seem to reach a large size. The smallest specimen is 

 only 2 mm. across the disk while the arms are more than 8; it 

 does not differ essentially from the adults but the side arm-plates 

 are relatively more conspicuous and hence the arms are more 

 ,, knotty", while the granulation of the disk covers the marginal 

 plates and there are a few granules on the oral side. 



There is some diversity of colour among the specimens at hand, 

 though the adults agree well with the holotype. The arms however 

 are sometimes quite distinctly banded. In one specimen most of the 

 disk is occupied by a symmetrical flower-like blotch of whitish and 

 in each interradius there is a conspicuous marginal spot of pure white. 

 The smaller specimens are as a rule paler and the smallest are nearly 

 white. Considerable diversity is shown in the number of "spiniform 

 grains" on the disk. In some specimens they are few (10-15) and 

 far between, while in other cases, they are quite numerous (75-100). 

 There is some diversity too in their height for while they are usu- 

 ally only 2-4 times as high as thick they are occasionally elongated 

 into little spinelets 5-6 times as long as their diameter. 



OPHIOMITRELLA CORYNEPHORA *, sp. nov. 

 Plate XIX. Figs. 5, 6. 



Disk 8 mm. in diameter; arms about 30 mm. long. Disk covered 

 by a coat of thin overlapping scales, most of which bear a single, 

 cylindrical (23 times as high as thick) granule with a rounded tip ; 

 there are many plates with no granules but there are very few that 

 bear more than one. Radial shields moderate, rounded triangular, 

 as wide as long, separated from each other by a series of scales, at 

 least one of which is granule-bearing; the radial shields themselves 

 bear no granules but the inner distal corner of each shield tends to 

 project as a low tubercle. Upper arm-plates small, diamond-shaped, 

 about as long as wide, widely separated and becoming very small 

 distally. Interbrachial areas below like disk but there are only three 

 or four granules in each area. Genital slits long and narrow, ex- 

 tending from oral shield nearly to disk-margin. Oral shields (except 

 madreporite) diamond-shaped, wider than long, the two proximal 

 sides lightly concave, the two distal lightly convex; madreporite more 



= club-bearing, in reference to the lowest arm-spines. 



