58 NATURAL HISTORY BULLETIN. 



The distal oral tentacle-pore is large and sub-marginal, 

 partly sheathed by proximal processes from the concave first 

 under arm-plate and inner side of the jaw. 



The adoral shields are very broad, but wholly proximal to 

 the small oral shields. The basal tentacle-pores are large 

 and furnished with two prominent tentacle-scales. 



The large, broad radial shields are largely in contact. The 

 disk-scales are not large, of nearly uniform size, without 

 specialized marginal ones, and bear short, coarse, clavate, 

 thorny stumps. 



The arm-spines are numerous, somewhat thorny and glassy. 

 The dorsal arm-plates are slightly separated by the side- 

 plates. 



Most of the species, subsequently described by Mr. Lyman 

 and others, differ much from the type in several characters. 



They nearly all have a single odd tooth-papilla and a 

 single row of mouth-papillae, as in typical Ophiacantha. The 

 interradial marginal scales are usually large and specialized. 

 The radial shields are often entirely separate and in some 

 cases not particularly large. 



Ophiomitra valida Lyman. 



Ophiomitra valida Lyman, Bull. Mus. Comp. Zool., I, 10, p. 325, 1869; 

 op. cit., X, p. 264, 1883; Lyman, 111. Cat. Mus. Comp. Zool., VI, pi. 

 II, figs. 4-6; Report Voy. Challenger, Zool., Ophiuroidea, V, p. 

 209, pi. XLI, figs. 4-6, 1882. 



Station 35, off Key West, 90 fathoms, eight examples; Sta. 

 33, off Sand Key. 105 fathoms, two examples; Sta. 56, Pour- 

 tales Plateau, 200 fathoms, one example. Found throughout 

 the Caribbcean Sea. at various depths, from 10 to 1105 fath- 

 fathoms. (Lyman). 



Ophiomitra ornata Ver. sp. nov. 



Plate V; Figures i, la. 



Arms five, spines numerous and very long, tapered, acute, 

 glassy, covered with small, rough prickles on all sides. Disk- 



