ASTEROIDEA 121 



('"' Triton "), in depths of ca. 930-1400 metres. It is not known 

 from other localities. 



Fig. 71. — Henricia ahyssicola, oral and dorsal side. Nat. size. 



III. Order. Forcipulata Perrier. 



Marginal plates generallj- inconspicuous, not forming a 

 vertical edge to the disk ; no sharp limit between dorsal and 

 oral side of disk and arms. Spines of dorsal side single, or in 

 groups, which may be arranged in longitudinal series. Tube-feet 

 mostly in four series, always with a sucking disk. Crossed and 

 straight pedicellarise present. Rays five or man}?-. 



Four families of this order are known from the British seas ; 

 a fifth, the family Pedicellasteridce, is almost certain to be 

 represented there also, though not hitherto recorded. This 

 family is included in the key ; the genera and species of this 

 family to . be expected in the British seas are briefly men- 

 tioned (p. 129). 



Key to the families of the Forcipulata known fro7n or likely to be 

 represented in British seas. 



1. Tube -feet in two series 1 ....... 2 



Tube-feet in four series at least in the proximal part of rays . 3 



2. Rays more or less constricted at the base ; dorsal skeleton of 



rays restricted to the proximal part. Long and slender 

 marginal spines enclosed in a bag of skin, covered with crossed 

 pedicellarise. No straight pedicellarise . I. Fam. Brisingidce 



^ Also one species of the Zoroasteridae, Prognaster GrimMdii, has the 

 tube -feet in the main biserial in the whole length of the ray, while otherwise 

 in this family the tube-feet are distinctly 4-serial in the proximal part of 

 the arms. In its whole appearance this species is otherwise a tyj^ical 

 Zoroasteroid, with very long, slender arms, and could never be mistaken 

 for being a Brisingid or a Pedicellasterid. 



