346 A. JEJ. Verrill — North American Ophiuroidea. 



Side arm-plates prominent, with the oblique, spine-bearing crest 

 near the distal margin, so that the spines are directed more or less 

 distally, especially on the distal half of the arm. One or two tooth- 

 papillae. Several simple oral papillae in a regular row, the outer ones 

 broader. One or two tentacle-scales. Arm-spines tapered, nearly 

 smooth, rather shoi't. 



This genus agrees with Ophiacantha and 0/)A^ow^^ra in its mouth - 

 parts, but differs from both in the more oblique position of the rows 

 of arm-spines and in the separation of the oral shields from the side 

 arm-plates. In the last character it agrees with Ophiopristis ^ Ophio- 

 pora, etc. 



The type, 0. Bairdii (Lyra., 1883,)* was taken by the Blake, off 

 the east coast of the United States, in 1242 and 1394 fathoms, and 

 by the United States Fish Commission Steamer Albatross in 1390 

 fathoms, in the same region. 



This species has seven or eight smooth, acute spines, of moderate 

 length ; the rows closely approximate dorsally ; the disk bears small 

 acute granules and a few short spines ; jaws partly naked, but with 

 some granules; outer oral papilla (oral tentacle-scale) broad and flat; 

 one tooth-papilla ; one small tentacle-scale ; oral shield broadly 

 obovate; dorsal arm- plates scarcely joined on basal joints. The 

 spine-crests are distally placed on the side arm-plates, and the spines 

 are mostly directed distally, or often lie nearly parallel to the arms. 



Ophiolimna mixta (Lym.) Verrill. 



Ophioehceta ? mixta Lyman, Bulletin Mus. Comp. Zool., vol. v, p. 223, pi. ii, 

 figs. 40-42, 1878; Voyage Challenger, Oph., vol. v, p. 110, pi. xxxix, figs. 

 15-17, anatomy, 1882. 



Ophiolimna mixta Ver., Ophiur. Bahama Exped., Bull., v, p. 40, 1899. 



This species has two large flat tentacle-scales ; seven smooth arm- 

 spines ; two tooth-papillae ; six oral papillae; jaws granulated; dor- 

 sal and ventral arm-plates not separated by the side arm-plates on 

 the basal joints ; disk crowdedly covered with granules mixed with 

 some slender spines. 



The internal structure, as figured by Lyman, is much like that of 

 Ophiacantha. The radial shields, seen from within, are broad, 

 three-cornered, separated. It does not appear to be closely allied to 

 Ophioehceta. 



West Indies, in 160 to 576 fathoms, Blake Exped. 



* Bulletin Mus. Comp. Zool., vol. x, p. 256, pi. v, figs. 70-72 (as Ophiacantha). 



