112 NATURAL HISTORY BULLETIN 



there is a small group of seven to ten more irregular plates, 

 closely joined and without inter^^ening papulae. On the radial 

 areas there is a median row of parapaxillae, not differing from 

 those adjacent. 



Around the center of the disk there are five interradial, round, 

 tabulate parapaxillge, more than twice as large as the others and 

 covered with similar rough spinules of which there may be six- 

 teen to eighteen marginal and ten to twelve in a central group. 



The small convex madreporic plate is attached to the outer 

 edge of one of these plates, which are united to five smaller 

 radial plates ; within these there is a group of six plates of which 

 one is central and a little larger than the others, which are like 

 the radials, and have intervening papular pores. No dorsal pore 

 is ordinarily visible. 



The inferomarginal plates agree closely with the upper ones 

 in size, form, ciliated grooves and spinulation, and stand exactly 

 opposite them. The interactinal plates are few relatively large, 

 thick, slightly lobed within, and are closely united or else slight- 

 ly overlap by their edges. They bear small, upright, rough, 

 acute spinules, six to eight surrounding a central one on the 

 larger plates. These plates form a continuous row of nine next 

 the adambulacrals with the impaired plate next the jaws. In 

 the second row there are about five small plates, with the median 

 one impaired. 



The adambulacral plates are small, short, rectangular, two 

 of them about correspond to one of the larger interactinals ; and 

 three distally to one marginal. Their inner margin is very 

 straight and bears an even row of four or five very slender sub- 

 equal spines, which completely interlock across the narrow groove. 

 On their actinal surface they have two upright, longer and some- 

 what larger acute spines, side by side ; on the adoral plates these 

 became decidedly larger and longer. On a few of the adambula- 

 cral plates there is an upright small two-valved, spatulate pedi- 

 cellaria. 



No pedicellarise were found on the upper side of this specimen, 

 but on some others a few of the dorsal plates have one or some- 

 times two, fossate pedicellariae with spatulate valves. 



It was taken by the Bahama Expedition on the crinoid ground, 

 off Havana, in about 200 fathoms. 



