ASTEROIDEA 123 



and Fr. tuberculata Sladen (S. of Canaries, between Cape Verde 

 and Ascension, 2350-2400 m.). 



These two genera therefore are included in the key. (A key 

 to the Freyella species is given below, p. 128.) 



Key to the genera of Brisingidoe known from or likely to he 

 represented in the British seas. 



1. Disk and genital region of arms with numerous, conspicuous 



papulae . . . . . .1. Odinia Perrier 



No papulae on either disk or arms ..... 2 



2. Dorsal skeleton of arms in the shape of raised arches, bearing 



small spinelets ........ 3 



Dorsal skeleton of arms a uniform armour of plates, not in the 

 shape of raised arches ....... 4 



3. Genital organs numerous, arranged in a series along either side 



of each ray ..... 2. Brisinga Asbjornsen 



Only one pair of genital organs in each ray 3. Brisingella Fisher 



4. An unpaired, conspicuous, shield - shaped oral interradial plate 



separates the first adambulacrals ; 7 arms Colpaster Sladen 



No unpaired oral interradial plate separating the first adambu- 

 lacrals. 6 (5)- 13 arms .... Freyella Perrier 



1. Odinia E. Perrier. 



Arms numerous (13-19), coalesced for a short distance at 

 their base. Dorsal skeleton of genital region of arms a mosaic 

 of plates, more or less distinctly arranged in arcs, which carry 

 long spines forming series across the arm. Disk and arms with 

 numerous papulae. One pair of genital organs to each arm. 

 Jaws laterally widened so as to separate almost completely the 

 ambulacral furrow from the mouth region. 



One species, Odinia pandina Sladen, known from the British 

 seas. Three more species have been recorded from the East 

 Atlantic and are likely to occur also in the British seas, viz. 

 Odinia rohusta E. Perrier (Bay of Biscay, S. of the Canaries, ca. 

 880-1750 m.) ; 0. semi-coronata E. Perrier (S. of the Canaries, 

 Denmark Strait, ca. 1000-1435 m.) ; and 0. elegans E. Perrier 

 (S. of the Canaries, ca. 880-1445 M.). It would seem not im- 

 probable that 0. rohusta and semi-coronata are in reality identical 

 with 0. j^andina ; from the description it does not appear clearly 

 which characters distinguish them from that species. No key, 

 therefore, can be given of these species, only reference to the 

 original description in Perrier's Echinodermes du " Travailleur " et 

 du " Talisman ". 0. elegans is a small form, distinguished from 

 0. i^andina through the transverse series of spines on the arms 

 being only slightly developed ; there are three complete series 



