452 s. GOTO : 



Iiiferomarginals. — These are confined to the actinal side of the 

 body and are generally larger than the corresponding saperomar- 

 ginals along the greater part of the arms, where they are penta- 

 gonal in outline. The six or seven plates in each interbrachial 

 are are smaller than those on the sides of the arms, more or less 

 mammiform and bear each a teat -like or bluntly conical spine at 

 the top, which is united with the plate by a presumably immova- 

 ble ball and socket joint. These spiniferous inferomarginals bear 

 some very small valvate pedicellariie, while the other j)lates, with 

 the exception of a few at the tip of the arms, bear either round 

 or more or less transversely elongated ones similar to those of 

 the superomarginals. The number of pedicellariae on one plate 

 may vary from 2 or 3 to about 10. The granules are exactly 

 like those of the superomarginals, except that those on the actinal 

 side of the interbrachial plates are coarser, and are more like 

 the granules of the adjacent ventrolateral plates. In each inter- 

 brachial arc there are intercalated between the two marginal series 

 3-5 ossicles, which are closely invested with granules exactly 

 similar to those of the marginals, and hence are not conspicuous 

 in surface view. 



AdamJmlacval plates, — The adambulacral plates are nearly 

 square in form when seen from the surface. The armature consists 

 of three rows of spines and some pedicellariae. The inner row is 

 well in the furrow and consists of nine or ten slender, rather 

 fragile spine 5 of very unequal lengths. On the first adambulacral 

 plate the tops of these spines form only a slight curve ; but the 

 curvature becomes pronounced very soon, and from the fourth or 

 fifth plate on these spines form almost a triangle with a rounded 

 apex, tlie spines at either end being very short. The top of the 



