cmuMi.] MADEIRA TO THE COAST OF BRAZIL. 65 



and the contraction of the proximal sides of these plates give 

 the arms a peculiar beaded appearance. The arm -spines are 

 seven in number on each side of two or three of the proximal 

 arm-joints, and usually five on the joints toward the middle of 

 the arm; they are long and glassy, and elegantly spinulated. 

 In color the perisom passes from a dark rose on the surface of 

 the disk and along the upper surface of the arms, tlirough paler 

 shades, to a nearly pure white on the under surface. 



This haul yielded, along with Opliiacantha chelys, the beau- 

 tiful little Ophiurid represented in Figs. 18 and 19. The diam- 

 eter of the disk is 5 mm., and the arms, which are rather wide 



Fig. is. — Ophiomiisium pulchellum, Wyville Thomson. Dorsal aspect of the disk. Seven 

 times the uatuial size. (No. 87.) 



at the base and taper rapidly, are only about once and a half 

 the diameter of the disk in length. The upper surface of the 

 disk is very regularly paved with thick, well-defined plates, each 

 of which rises in the centre into a pointed tubercle approaching 

 a spine in character. One almost regularly hexagonal plate oc- 

 II.— 5 



