Benham. — Stellernh and Echinii/x from the Keritiadtcs. 15o 



The adiadial. the bhint tip of which is free and slightly raised, is also 

 covered with spiuules, though more sparsely than elsewhere. 



The actinal interbrachial area is naked except for a small triangular 

 patch of spinules which encroach from its margin. 



The orals are remarkably small, and only that carrying the madreporite 

 is at first noticeable, owing to its larger size. They are transversely 

 rhomboid, situated close to the outer margin of the actinal region, near the 

 genital clefts, leaving the whole of the angle-pieces, as well as the conspicuous 

 perforation between them, exposed. 



The torus is broad. There are no buccal papillae, but a large series of 

 16 dental papillae, which form a vertically oval patch, arranged in four 

 horizontal rows of 4 in each row. 



Fig. ]4. — Ophiothrix nliveri. 

 Actinal surface of portion of the disc (x 5). 



The upper arm-plates are naked, transversely oval, with the proximal 

 margin straight. This margin has a raised median prominence, pale in 

 colour, while the distal margin has a small peak, also pale. The successive 

 plates are in contact (fig. 15). 



The under arm - plates are subquadrate, broader than long, the 

 proximal margin nearly straight, the distal concave, the lateral borders 

 convex (fig. 17). 



The arm-spines are 8 in number, glassy, flattened, and feebly thorny 

 along the edges. The lowest spine (1st) is the smallest, being only a little 

 longer than the scutellum or tentacle-scale, just outside which it lies. The 

 next 2 are successively longer, while the -Ith, 5th, and 6th are the longest : 

 these approximately equal four lengths of a dorsal arm-plate. The 7th and 

 8th are successively shorter ; the 7th is nearly twice the breadth of a dorsal 

 plate, while the uppermost is rather less than the length of this plate. The 

 spines are violet (fig. 16). 



The arms are (in alcoholic specimens) coloured with violet bands, 

 alternating with paler, somewhat greenish, bands of less width. The violet 



