A. E. Verrill — North American Ophiuroidea. 369 



This family, as here defined, includes only two described genera : 

 Gorgonocephalus and AstropJiyton. To these should be added a 

 third, to include Euryale verrucosmn Lam., which differs much 

 from both the others. For this I propose the name Astrocladus. 



Astrocladus Verrill, gen. nov. 



Resembles Gorgonocephalus in form, but differs in having no 

 pavement of plates on the mai'gius and interradial areas ; in the 

 absence of under arm-plates ; in having no minute hooks on the arm- 

 ridges ; in having no spines or tentacle-scales on the basal points ; 

 in having the side arm-plates more degenerate, and not covering all 

 of the under side of the arms, leaving spaces of naked cuticle 

 between them. The arms have very numerous forks. 



The type, A. verrucosus (Lam.), has rather large, rounded or 

 verruciform tubercles, arranged in two irregular rows along the 

 upper side of the arms and on the radial ridges of the disk. 



There are usually three short, stout, obtuse tentacle-scales, thorny 

 at the tips. 



The tooth-papillse and teeth are very numerous, elongated, spini- 

 f orm. The oral papillse form two or more rows ; the larger ones are 

 cylindrical or spiniform, the smaller ones conical. 



The whole surface of the arms and disk, above and below, is 

 covered with fine and close granules. The annulations of the arms 

 are not very prominent. 



The forkings of the arms are very numerous, with short inter- 

 nodes. The arms are stout at the base. 



The adoral and oral shields are represented by a group of irregu- 

 lar plates. The interradial areas below are covered with thin gran- 

 ulated cuticle, without plates. 



It has been recorded from the Cape of Good Hope, etc. A speci- 

 men in the Yale Museum is labeled as from Japan, but this locality 

 may possibly be erroneous. 



Family, ASTROCHELID^ Verrill. 



Astrochelidce Verrill, Ophiur. Bahama Exped., p. 79, 1899. 



Arms simple or with a few distal forks, granulated, and also 

 annulated with raised ridges. Disk with five or ten radial ridges, 

 its surface granulated or spinulose. 



The genital openings are short, situated toward the margin of the 

 disk, or not close to the inner angles. 



Under arm-plates rudimentary or lacking. Side arm-plates cover 

 most of the under surface, but are hidden by cuticle and granules. 



