The Echinodenn Fauna of South Africa. 261 



the inferomarginals; there are 8-10 on that margin, 8 or in the 

 marginal series up each side and 18-20 on the semicircular inner 

 (upper) margin; the second, third and fourth superomarginals are 

 similar but progressively slightly smaller and with more square cut 

 inner ends; on the fifth plate is a small bare area and this increases 

 in size on the succeeding plates, until on the distal plates only a 

 marginal series of granules remains; the last three superomarginals 

 of the two sides meet in the midradial line, so the abactinal plates 

 do not reach the terminal plate; the latter is of moderate size, 

 rounded triangular or pentagonal and decidedly swollen. Madreporite 

 small, only 1*5 mm. in diameter, its outer margin 12 mm. from edge 

 of disk. Inferomarginals 14 or 15 on each side, always one more 

 and sometimes two more than the superomarginals of the same side ; 

 in the neighborhood of the sixth superomarginal there are two infero- 

 marginals and at the tip of the ray another extra inferomarginal is 

 often to be found ; the inferomarginals are very similar in form and 

 granulation to the adjoining superomarginals. Actinolateral plates 

 numerous, but so crowded and so closely granulated that the series 

 can be made out only with difficulty; that adjoining the adambulacral 

 plates extends to the eighth inferomarginal while the next series 

 reaches only to the sixth ; the granulation is much coarser than that 

 on the marginals or abactinal plates and is well-spaced ; there are 

 rarely as many as 20 granules on a plate, 



Adambulacral plates about 50 in each series, short and crowded, 

 much wider than long except distally where the length nearly equals 

 the width. Each plate carries a series of 3 (or rarely 2) stout spines 

 on the furrow margin ; these spines are a millimeter long, subequal, 

 blunt, cylindrical or more or less compressed ; back of this series, 

 there are on the oral surface of each plate, three pairs of spines; 

 the first (innermost) of these is much stouter and a little shorter 

 than the furrow-spines, and the distal spine is larger than the 

 proximal ; on the terminal part of the arm, this larger spine becomes 

 quite conspicuous as relatively the biggest adambulacral spine ; the 

 other two pairs of spines are much smaller, and the outer one is 

 scarcely larger that the granules of the actinolateral plates; on some 

 adambulacrals, one (or even two) of these six surface spines is wanting. 

 Oral plates not at all swollen; on each free margin is a series of- 5 

 or 6 stout, more or less prismatic, subequal spines; just back of these 

 is a series of 5 similar but shorter spines, and on the distal part of 

 each plate are about 5 still shorter spines or coarse prismatic granules. 

 There seem to be no pedicellariae anywhere. Color of dried specimen, 

 uniformly dingy, brownish-yellow. 



