104 Bulletin, Vanderbilt Marine Museum, Vol. TV 



Habits: This curious animal has a body composed of over 81,000 

 joints. It walks on the tips of its branches and arches the central 

 portion upward. The multibranched arms serve as shelter for a 

 number of species of small crustaceans, mollusks and ophiurans, some 

 of which are external parasites, feeding on the food particles col- 

 lected by the basket-fish. The network of arms of the basket-fish 

 make a complete trellis and serve to enmesh small animals, i. e., cope- 

 pods, snails, worms, small fish, etc., on which the basket-fish feeds. 

 The arms carrying food curl up, passing it into the star-shaped mouth. 



Technical description : This species, which is easily distinguished 

 by the fact that the radial ribs of the disk are decidedly, sharply 

 elevated, bearing a few large, fleshy spines, the sides of which are 

 usually conspicuously fluted, is monotypie of the genus as at present 

 restricted. 



Diameter of disk 70 mm., from the outer corner of madreporic shield 

 to the outer corner of the opposite mouth-slit 29 mm. ; width of arm 

 at base 24 mm. It is impractical to give the length of distances of the 

 forks of the arms because of their dried and interlaced condition. 



The teeth, tooth papillae and mouth papillae are sharp, conical, of 

 unequal sizes. Eight to ten of these which occupy the place of teeth 

 are largest, attaining a length of 3 to 3.2 mm. Those representing 

 the mouth papillae are of intermediate sizes. The outer mouth papillae 

 extend down to the outer corner of the mouth-slit. The madreporic 

 plate is of irregular shape, somewhat between a rectangle and an oval 

 in contour and is situated near the inner angle of the interbrachial 

 space. The arms are covered above, below and on the sides by a close, 

 fine, smooth pavement of microscopic granules. Transverse lines dis- 

 tinctly indicate the joints of the arms on the aboral surface and sides ; 

 on the oral surface there is a definite longitudinal sunken line, here 

 are also scattered round spots composed of concentric rings of micro- 

 scopic oblong round grains. On the outermost branches most of these 

 grains form a double vertical row of grains which support the arm- 

 spines, each of the latter being a single microscopic hook. 



The disk, which is covered on both surfaces with the same granular 

 covering as the arms, has also above the round spots in the inter- 

 brachial spaces. The paired radial ribs are very prominent, terminat- 

 ing outwardly in a smooth, concave cicatrix. On the median upper 

 surface of each is an irregular, longitudinal series of coarse spines, 

 1.5 to 2 mm. high, with their sides deeply fluted. The under inter- 

 brachial spaces are very small because of the great breadth of the 



