296 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. 



Under arm-plates separated beyond third or fourth. 



Basal upper arm-plates broadly in contact variabilis. 



Basal upper arm-plates separated beyond second undata. 



Under arm-plates not separated until at least the sixth. 1 

 Disc covered chiefly by 6 primary plates, 10 radial shields, and 5 large in- 

 terradials; a large interradial plate just outside oral shield ventrally 



Jasciculata. 

 Disc covered by numerous small plates, among which primary plates are 

 not conspicuous ; no large interradial plate outside oral shield sterea. 

 Arm-spines 6 (rarely 5?) or more. 



Arm-spines not more than 7 sculptilis. 



Arm-spines not less than 9 lapidaria. 



Ophiocoma brevipes. 

 Peters, 1852. Arch. f. Naturg., 18 (1), p. 85. 



6 specimens. Diameter of disc, 9-17 mm. Color of disk yellowish-brown, 

 with more or fewer dark spots ; arms variegated olive and yellowish with narrow 

 dark cross-bands. Amboina. — 3 specimens. Diameter of disc 10-12 mm. 

 Color of disc variegated light and dark brown ; arms as in Amboiua specimens. 

 Sorong, New Guinea. Barbour collection. 



Ophiocoma erinaceus. 



Midler & Troschel, 1842. Sys. Ast., p. 98. 



1 specimen. Diameter of disc, 8 mm. Color above and below deep purplish- 

 brown, the spines strougly tinged with red. Amboina. Barbour collection. 



This specimen is so easily distinguished from the other Ophiocomas in the 

 collection that I am loath to accept the view held by Koehler aud others that 

 erinaceus is only a variety of scolopendrina. 



Ophiocoma schoenleinii. 



Miiller & Troschel, 1842. Sys. Ast., p. 99. 



3 specimens. Diameter of disc, 9-15 mm. Color above and below deep 

 purplish-brown, almost black ; proximal margin of under arm-plates whitish ; as 

 tip of arm is approached, the light color becomes more extensive, especially later- 

 ally, passing up on the side arm-plates to the upper surface, until at the extreme 

 tip the arm is prettily banded witli white and brown. This peculiar type of 

 coloration is occasionally seen in specimens of erinaceus. Amboina. Barbour 

 collection. 



1 Lyman says in his description of fnscicidata, side arm-plates " meeting neither 

 above nor below," but his figure shows them apparently in contact beyond the 

 sixth under arm-plate. 



