602 



THE VOYAGE OF H.M.S. CHALLENGER. 



The genus Brisinga as now defined is limited to those forms in which the abactinal 

 skeleton of the rays is confined to isolated transverse ridges limited to the basal portion of 

 the ray, and in which the abactinal membrane is entire, and not punctured by papulae. 



b. 



coronata. 



veriieiUata. 



Synopsis of the Species included in the Genus Brisinga herein described. 



A. Transverse calcareous ridges prominent and robust. 



a. Rays robust, nine to thirteen in number. Transverse ridges broad and 



robust (15-20 in number). Ambulacral tube-feet not separated by- 

 two spinelets .......... 



b. Rays delicate, eight in number. Transverse ridges thin and high 



(10-112 in number). Ambulacral tube-feet separated by two 



horizontally placed parallel spinelets 



I!. Transverse calcareous ridges moderately prominent or more or less rudi- 

 mentary. 

 a. Ridges complete. Tegumentary prickles in the abactinal membrane. 



a. Rays eleven in number. Ambulacral tube-feet not separated by 



two equal horizontally disposed spinelets. 



a. Adambulacral armature with three inner spinelets, all small 

 Actinal spines at base of ray needle-like. With 

 crowded spinelets on the transverse ridges .... 



p. Adambulacral armature with two inner spinelets, one large. 

 Actinal spines at base of ray robust, clavate, with a 

 coronate extremity. With widely spaced spinelets on 

 the transverse ridges ....... 



b. Rays seven in number. Ambulacral tube-feet separated by two 



equal horizontally disposed spinelets ..... 

 Ridges incomplete and more or less rudimentary. Xo tegumentary 

 prickles in the abactinal membrane. 



a. Adambulacral armature with one inner spinelet. Lateral spines 

 short. Calcareous ridges feebly developed ..... 



b. Adambulacral armature with three or four inner spinelets. Lateral 

 spines long. Calcareous ridges rudimentary, never complete 



endecacnemnx. 



cricophora. 



armillata. 



membranacea. 



discinda. 



Chorology of the Genus Brisinga. 

 a. Geographical distribution : — 



Atlantic : Six species between the parallels of 10° and 70° N. 



Brisinga coronata, off the Lofoten Islands, the west coast of 

 Norway, south of Eockall, west coast of Ireland, and west coast of 

 Spain. Also in the Mediterranean, dredged by the " Travailleur " 

 and " Talisman " (fde Perrier). Brisinga endecacnemos, off the 

 west coast of Norway, between the Faeroe and the Shetland Islands, 

 off the south-Avest coast of Ireland, in the Bay of Biscay, west of 

 Ushant, and off the west coast of Spain. Brisinga mediterranea, 

 between Marseilles and Corsica. '"Brisinga cricophora, north- 



