I4 NATURAL HISTORY BULLETIN. 



Ophiomusium testudo Lyman. 



Ophiomusium testudo Lyman, 111. Cat. Mus. Comp. Zool., VIII, 2, p. 

 8, pi. I, fig. 6-8, 1875; Bull. Mus. Comp. Zool., V, 9, p. 219; Lyman. 

 Report Voy. Challenger, Zool., Ophiuroidea, V, p. 99, 1882. 



Sta. 2 and 13, off Havana, in no fathoms, thirteen ex- 

 amples; sta. 56, Pourtales Plateau, in 200 fathoms, four ex- 

 amples. Taken by the Blake Exp. in 73 to 400 fathoms. 



Ophiomusium stellatum Verrill, sp. nov. 

 Plate I; Figures 3. 3«. 

 Disk nearly round, rather thin and flat, with a ten-rayed 

 grouping of small crowded plates. Arms five, of moderate 

 length, slender, regularly tapered, with the joints rather 

 prominent, owing to the projecting side arm-plates. Radial 

 shields rather large, ovate, divergent, separated by about 

 three crowded, irregular rows of unequal overlapping plates, 

 those of the middle row larger. A large, thickened, super- 

 marginal, interradial plate, nearly as large as the radial shields, 

 occupies most of each interradial margin, between the radial 

 shields with which it is in contact on each side, within the 

 outer margin, but they are separated distally from it by a 

 small, rounded marginal plate on each side. This large inter- 

 radial plate is somewhat semicircular in form, with the convex 

 edge turned toward the center of the disk, while its gently 

 curved or nearly straight outer edge forms the interradial 

 border of the disk. From each of the large interradial plates 

 three or four crowded rows of small unequal plates extend in- 

 ward to the central area, forming five rays, somewhat broader 

 than the radial rays, but giving a distinctly ten raved character 

 to the disk-scaling. On the central area of the disk is a larg- 

 er, round, central plate and ten similar primary plates can be 

 distinguished among the small, unequal, crowded scales. 



Just outside the distal end of each radial shield there is a 

 small, thick, transversely elliptical plate, which rises promi- 

 nently above the level of the radial shields and arm-plates. 

 Distal to this there are two or three small supplementary 

 basal arm-plates. 



