SEA LILIES, STARFISHES, ETC. CLARK. 37 



apparently about 2 mm. Breadth at proximal margin of 

 first superomarginals which meet=length of first three supero- 

 marginals (comiting from interradius). Disk flat, rather 

 large ; rays moderately long and quite narrow, all broken at 

 tip, but one seems to be nearly complete, quadrangular in 

 cross-section with very sHghtly rounded angles, the width 

 shghtly exceeding the thickness, at all points. Abactinal 

 plates entirely confined to disk, forming an almost perfectly 

 pentagonal area, the sides of which are so sHghtly concave 

 as to appear ahnost straight ; there are 650-700 plates in this 

 area but most of these are verj^ small and he along the 

 boundaries formed by the superomarginal plates ; the largest 

 abactinal plates are near the centre of the disk in the inter- 

 radii and along the midradial lines. At the centre of the 

 disk and in the rachal areas where the papulae occur, the 

 plates are more or less stellate or substellate basally, the upper 

 surface being roimded pentagonal or subcircular ; each plate 

 carries 15-25 coarse granules, nearly spherical and not at all 

 rough, those of the marginal circle not being appreciably 

 different from the rest ; near the superomarginal plates, the 

 abactinal plates are so small and crowded, the granules tend 

 to form a continuous coat with those on the superomarginals. 

 The latter are apparently rather more than 20 on each side 

 of each ray, and excej^ting the basal 4 pairs are in complete 

 contact in the midradial line ; they are very flat, not at all 

 tumid, and in the interbrachial arcs overhang the infero- 

 niarginals ; eight superomarginals make up each side of the 

 disk-pentagon ; they are wider than long, the middle pair 

 being each 5 mm. A\ide by 2.5 mm. long ; at the middle of the 

 arm the superomarginals are each about 2 mm. long, 2 mm. 

 wide, and 1.5 mm. thick ; all the superomarginals are covered 

 by a uniform coating of granules similar to those on the 

 abactinal plates ; these are largely rubbed ofl' in the present 

 specimen ; on the entire surface of each of the middle pair of 

 superomarginals, there are about 200 granules. 



Inferomarginals coincide in number and j)Osition with the 

 superomarginals (except when regeneration has occurred), but 

 owing to the presence of the ambulacral groove they are much 

 narrower ; at the middle of the arm they are about 2 mm. long, 

 1 mm. wide and 1 mm. thick ; hke the superomarginals, they are 

 clothed with a close coat of granules, each one of the middle 

 pair carrjang about 150. Actinal intermediate plates wanting 

 on rays ; the series adjoining the adambulacral plates, extends 

 only to the fourth inferomarginal and contains 10-12 j^lates ; 

 •outside of it is a series of 6-8 plates, then a series of 5-6, then 



