OPHIUROIDEA OF THE BAHAMA EXPEDITION. 67 



Oral shields small, broad-elliptical or sub-rhombic, with 

 rounded corners, rather broader than long. Adoral shields 

 trilobed, separating the oral shields from the side-plates, but 

 not meeting within. 



Diameter of disk, 13 mm. Length of arms, 45 mm. 



Stations 4 and 13, off Havana, in no and 200 fathoms. 



This species has arms shorter and much stouter at base 

 than the preceding, and they taper very rapidly, instead of 

 being of nearly uniform breadth and slender. The arm- 

 spines are more slender, less tapered, rougher, and more 

 glassy. The tentacle-pores are much larger; the under arm- 

 plates are less heart-shaped or triangular; the mouth-papillae 

 stouter; the marginal disk-scales larger. 



Ophiomyxa tumida Lyni. 



Ophiomyxa tumida Eym., Bull. Mus. Comp. Zool., vol. X, p. 272, pi. I, 

 figs. 1-3, 1883. 



Plate III; Figure 5. 



This species was taken at many stations in the West In- 

 dian region, in 13 to 300 fathoms by the Blake Expedition. 



Ophiodera, gen. nov. Type, O. ser-pentaria (Lym.) 



Marginal disk-scales are rudimentary and concealed by 

 thick cuticle; the disk-scales proximal to the radial shields, 

 are lacking. No upper arm-plates. Side arm-plates may be 

 soldered to the under arm-plates. They are not continued 

 upward by a row of small plates. Three or four arm-spines 

 enclosed in cuticle, the inner one is smaller and may serve as 

 a tentacle scale; it is sometimes forked distally. Teeth and 

 tooth-papilla? serrate, nearly as in Ophiomyxa, but with finer 

 denticles. 



Ophiodera stimpsoni Verrill. 



? Ophioscolex stimpsoni Lyman, Illust. Cat. Mus. Comp. Zool., VIII, 

 p. 23, pi. I, figs. 11-15, 1875. 



