t)2 PROCEEDINGS OF THE ACADEMY OF [Feb., 



well-developed articular condyles and sockets. Peristomal plates 

 large, usually entire. Oral frames entire, without well-developed 

 lateral wings. Dorsal arm plates often very small, while the lateral 

 arm plates are very well developed, those of opposite sides usually 

 meeting both above and below. 



Key to families of Lcemophiurida. 



A — Disk and arms delicate and slender; disk scales or plates, as 

 well as arm plates, not very stout, genital plate and scale of 

 either side of a radius articulate with each other, instead of 

 being soldered together; vertebrae not very stout, distal ones 

 often incompletely divided longitudinally by a series of 



pores OPHIACANTHIDiE. 



A A — Disk and arms very heavy; disk and arm plates very stout; 

 genital plate and scale of either side of a radius, firmly soldered 

 together; vertebrae very stout Hemieuryalid^e. 



Family 1. OPHIAOANTHIDiE (Perrier, 1891) Verrill, 1899. 



(Characters as given above in key.) 



This family includes Ophiotholia, Ophiornyces, Ophiologimus, 

 Ophiophrura, Ophiotoma, Ophiohlenna, Ophiocymhium, Ophiopora, 

 Ophiotrema, Ophiomedea, Ophiopristis, Ophiolimna, Microphiura, 

 Ophiomitrella, Ophioscalus, Ophiocopa, Ophiacantha, Ophiacanthella, 

 Ophiolehes, Ophiochondrella, Ophiothamnus, Ophiomytis, Ophioplin- 

 thaca, Ophiomitra, Ophiocamax, etc. 



Ophiacantha bisquamata sp. nov. 



Diameter of disk 6 mm. Length of arms 34 mm. Width of 

 arms at base 1.5 mm. Disk pentagonal, with nearly straight or 

 slightly convex interbrachial borders, closely covered with fine 

 granules, of which eight or nine lie in 1 mm. Radial shields entirely 

 concealed, very small, bar-like, separated from each other. Ventral 

 interbrachial areas similar to the dorsal side, but proximally free of 

 granules and covered with fine scales. Genital slits long, nearly 

 reaching the disk margin. 



Oral shields small, rhomboidal, with convex inner sides and rounded 

 outer angle, nearly as long as, or slightly longer than wide, in contact 

 with the first lateral arm plates. Adoral shields small, triangular, 

 pointed inwards, meeting each other. Five or six oral papillae on 

 either side of each jaw; the outermost two are flat and leaf -like, 

 protecting the second oral tentacle pore; the others are very narrow 

 and acute; the innermost one, which pairs with that of the other 

 side, is infradental. Four or five teeth in a single vertical row, more 



