A. E. Verrill — North Amei'ican Ophiuroidea. 371 



Teeth stout, well formed, in a single row. Tootb-j^apillse one or 

 two, conical, sometimes absent. Oral papillae small, like conical 

 granules, placed above the margins of the jaw. Oral and adoral 

 plates regularly formed. 



Astronyx was the only described genus of this family, till recently, 

 when I added to it a new genus, Astrodia (type, A. temcispina 

 Ver.), from deep water off the U. S, coast. 



Astronyx Lymani Verrill. 



Astronyx Loveni Lyin., Bull. Mus. Comp. Zool., vol. x, p. 383, pi. viii, figs. 



136-138, young (non Miill. and Troscliel). 

 Astronyx Lymani Verrill, Ophiur. Bahama Exped., v, p. 74, pi. viii, figs. 

 4-4e, 1899. 



Plate XLII. Figures 6-6c. 

 Arms five, long, slender, coiled. Disk pentagonal with incurved 

 margins, and ten high, long radial shields, which are widely sepa- 

 rated, curved outward in the middle and somewhat sinuous distally, 

 the outer end a little clavate or knobbed ; the edge is serrulate with 

 small scales. The radial shields and disk are covered with a thin, 

 smooth skin which extends out on the arms, above and below. Inter- 

 brachial region below, in the dry specimen, concave or sunken, with 

 the two short but wide genital openings close together, near the 

 inner angles. 



Astrodia Verrill. Type, Astronyx (?) tenuispina Ver. 

 Astrodia Verrill, Ophiur. Bahama Exped., p. 74, 1899. 



Disk small; arms very long, slender, much coiled. Upper and 

 under surfaces of the disk and arms covered with thin, delicate, 

 closely imbricated scales, without granules. 



Under arm-plates not distinct, excej)t on one or two basal joints. 



Arm-spines three, except on a few basal joints, rather long, 

 tapered, simple, thorny at the tip, but not becoming hooked, even 

 on the distal part of the arms. 



Teeth stout, obtuse, the lowest not differing much from the rest. 

 No tooth-papillae. A row of small granule-like oral papillae. Oral 

 and adoral shields well developed. 



The type-species lives clinging, by its coiled arms, to a species of 

 slender, pennatulid coral [Scleroptilum gracile V.), in 1362 to 2033 

 fathoms, off the United States East Coast. (See Amer. Journ. 

 Sci., vol. xxviii, p. 219, 1885; and Annual Rep. U. S. Fish. Com. for 

 1883, p. 550 (as Hemieiirycile tenuispina). 



