REPORT ON THE OPHIUROIDEA. 



169 



Peristomial 

 plate. 



Spines. 



Radial 

 shields. 



Genital plate 

 and scale. 



Teeth and 

 tooth papillae. 



Arm bones. 



( >/ilt iocoma miliaria. 



Thin, in three pieces, with a 

 crust over outer open angle 

 as in Ophiocamax. 



Hollow, round, standing on 

 outer edge of side arm 

 plate. 



Rounded. 



Plate flattened 

 head, 

 shape 



with longish 

 Scale long and blade 



Teeth simple. 



Thin rim ; faces normal about 

 as in Ophiocoma. 



Opkiocoma antarctica. 



Thick, in one or two pieces as 

 in Ophiacantha. 



Hollow, round, standing on 

 outer edge of side arm 

 plate, but at an angle. 



Small, narrow, no scale rows 

 in any of the three species. 



The same. 



Teeth with few tooth papillae. 



The same. 



OpJt iocoma nigra. 



Thick, in two pieces. 



Hollow, somewhat ilat on 

 sides of side arm plate, and 

 at a right angle to arm. 



Scapula shape. 



The same. 



Teeth and many tooth papil- 

 lae as in true Ophiocoma. 



The same. 



As well as I can judge from description and figures and my own notes, Ophioconis 

 forbesii would be of the same genus as Ophiocoma miliaria. Ophiocoma antarctica 

 differs in having arm spines at somewhat of an angle ; different peristomial plate and a 

 few tooth papillae. Ophiocoma nigra differs as does Ophiocoma antarctica, and also in 

 numerous tooth papillae, and in spines at a right angle to the arm ; being in these two 

 respects a true Ophiocoma. All three species agree in — (1) hollow spines, (2) genital 

 plates, &c, (3) arm bones, (4) disk scaling and outer granulation. Ophiocoma nigra 

 differs from Ophiocoma in hollow spines ; in peristomial plate, and in radial shield 

 without any scale lines. 



See Plate XLII. figs 9-13. 



Table of Species of Ophiocoma. 



Arm spines ringed with darker and lighter, .... 



Oph iocoma seolopendrina. 



Arm spines not ringed. Central disk scales much coarser and thicker than ) n , 

 • H. a- t Ovh 



in the preceding, . . . . . . ■ i 



uoroma erinaceus. 



_. , ., . f Ophiocoma wendtii. 



Doubtful species \ Ophiocoma schoenleini. 



S -l Upper arm spine swollen. Upper arm plates narrow. Mouth shields ) ,-. , . , . . 



_3 i t-f r « t- \ Ophiocoma ecu mat a. 



squarish, . . . . . . . ■ ) 



Disk closely and finely granulated above and below (in other species scattered, 1 n , . , , . 



3 1 1. 1 \ TT 1 i 1 J 1 f LsPfl 10t'0)}ia f'/'' /'//" V, 



and almost none below). Upper arm plates regular and clean cut, • J 



Doubtful species, ........ Ophiocoma mpiamata. 



Arm spines regular, tapering, and pointed. Coloration variegated, . . Ophiocoma pica. 



