244 THE VOYAGE OF H.M.S. CHALLENGES. 



2. Antedon inasqualis, n. sp. (PI. II. figs. 5, a-d ; PL LI. fig. 2 ■ woodcut, p. 246, 

 fig. 5, A ; also Part I. pi. liv. fig. 8). 



Specific formula — A. 3. — 9~~-"y- 



Centro-dorsal hemispherical, rather flattened at the dorsal pole, and bearing twenty 

 to twenty-five cirri. These have about twenty joints, a few of which are longer than 

 wide ; the later ones are somewhat compressed laterally and more or less distinctly 

 carinate ; the penultimate with an opposing spine. 



First radials partially visible above the angles of the centro-dorsal; the second 

 short, sharply convex, and closely united laterally. Auxiliaries short, broadly pentagonal, 

 and very convex iu the centre, forming a median tubercle with the second radials. 



Three distichals with a syzygy in the axillary, which is in close contact with its 

 fellow on the next ray, and another syzygy between the first two brachials. These five 

 joints, and in a less degree also the two outer radials and the third brachials, are in 

 close lateral contact and very distinctly wall-sided, with sharp edges and the margins 

 of the dorsal surface a little depressed. The second, and occasionally also the third, 

 brachial may likewise be slightly flattened on both outer and inner sides. One 

 specimen has two palmars united by syzygy, and another two with the axillary a 



syzygy. 



Eleven to twenty arms of some one hundred and twenty joints, the lowest nearly 

 oblong, and the following ones triangular, as long as wide, and gradually becoming more 

 cpaadrate. The pieces of the calyx and the lower parts of the arms often have some- 

 what prominent edges. On the arms, which start directly from the radial axillary, the 

 third brachial is a syzygial joint, and the next syzygy is between the fourth and 

 the thirteenth brachials ; but when distichals are present the first two brachials are 

 generally united by syzygy, and the next syzygial joint is from the seventh to the 

 tenth brachial. After this there is an interval of two to fifteen, usually four to seven, 

 joints between successive syzygia. 



The second distichal bears a small pinnule, 7 mm. long, which consists of some 

 twenty to twenty-five short joints, the lowest of which, and especially the first, are 

 wide, trihedral, and flattened against the arm, while the remainder are slightly carinate. 

 The next pinnule (on second brachial) is a trifle longer, with relatively long terminal 

 joints, and the basal ones less wide and more carinate. The third and following 

 brachials have stdl longer and stouter pinnules (12 mm.), with the outer edges of the 

 third and the two to four following joints much produced towards the ventral side, so as 

 to give them a broad and flattened appearance. The length of the pinnules decreases 

 somewhat after the sixth brachial, but the expansion of their lower joints is traceable 

 till the fifteenth or twentieth, after which they become more slender, with only the two 

 lower joints wider than long. Disk much incised and completely plated, as are also the 



