156 Bulletin American Museum of Natural History [Vol. XL VIII 



Tentacles long and basally large, scarcely contracted at all. Tentacle pores large, 

 guarded by three tentacle-scales which were apparently somewhat spiniform, but 

 as all are broken at the tip their actual form is uncertain. 



Interbrachial spaces below covered with thin, soft skin, with a few spine-bearing 

 scales like those of the dorsal surface; these are most numerous, naturally, near the 

 disk margin and are wanting near the mouth. Genital slits conspicuous, especially 

 orally, margined by well-developed genital plates and at the oral end by the adoral 

 plates and side arm plates. Oral shields conspicuous, nearly three times as wide as 

 long, except the madreporite in which the length almost equals the width; the proxi- 

 mal margin has a distinct sharp median angle, but the narrow lateral angles are 

 rounded. Adoral plates L-shaped, the tip of each branch expanded, especially the 

 shorter; they meet broadly in front of oral shield, but abut on the first under arm 

 plate at the other end. Oral plates rather large and a little swollen. Teeth in a 

 vertical series of about 4, bluntly pointed, about twice as long as wide. Oral papillae 

 4 on each side, the smallest ones distalmost, the largest at apex of jaw; the largest 

 are as long as the teeth but not quite so wide. Besides the oral papilla?, the sides of 

 the jaw are armed with conspicuous oral tentacle-scales; the first oral pore is guarded 

 by two large ones, as big as the smaller oral papillae but of course above them 

 (apparently below, when the mouth-parts are being examined); the outer pore is 

 guarded by three similar spiniform scales which are nearly at the same level and in 

 line with the oral papillae. Color pale gray. 



Type.— Cat. No. — , U. S. Nat. Mus., from Station 5694. 



Station 5694. Southwest of Santa Cruz Island, California, 640 

 fathoms. 



One specimen. 



The actual relationships of this brittle-star are dubious, owing to 

 the defective condition of the specimen. The swollen disk and dorsally 

 contracted arms, with the apparent absence of radial shields, remind one 

 of Ophiotholia, but the mouth-parts are quite like many species of 

 Ophiacantha. If the distal part of the arms were present, we should be 

 better able to decide whether the relationship to Ophiotholia is at all 

 close. Under existing conditions, it seems better to put the species in 

 Ophiacantha, although it is obvious that it is not closely related to any 

 species of that genus. The whole family of the Ophiacanthidae needs 

 revision with a careful comparison of internal skeletal plates which have 

 hitherto been largely ignored. When this revision is made there will no 

 doubt be a considerable increase in the number of genera which should be 

 recognized. 



Ophiocoma eethiops Liitken 

 Ophiocoma aethiops Lutken, 1859, 'Add. ad Hist.,' pt. 2, p. 145. 

 A very small brittle-star bearing every indication of being an 

 Ophiocoma, and certainly not 0. alexandri, is referred to this Panamic 

 species. The disk is less than 2 mm. across, prettily variegated, as are 



