ECHINOIDEA 



345 



always as high as is the figure), which continues as a distinct 

 prominence over the periproct. The larger tubercles of the 

 antero-lateral ambulacra arranged in a fairly conspicuous trans- 

 verse series on each plate, the posterior tubercle in each series 

 being the largest. The primary spines are of rather uniform 

 length, the longest scarcely exceeding one-third the length of test. 

 Globiferous pedicellarise do not seem to occur. The tridentate 

 and triphyllous pedicellariae are not characteristic, small with 

 simply leaf -shaped valves. The ophicephalous pedicellariae are 

 very elegantly shaped, the valves being slender, with deeply 

 serrate outer edge (Fig. 206, 3). The rostrate pedicellariae. 



;?oo: 



Fig. 206. — Rostrate pedicellaria of Pourtalesia Wandeli (1) and of Pourt. 

 Jejfreysi (2) ; ophicephalous pedicellaria of Pourt. Jeffreysi (3). x 55. 

 (After Th. Mortensen, " Ingolf '' Ech., ii.) 



which are fairly conspicuous, up to 0-5 mm. length of head, and 

 more or less darkly pigmented, have rather slender valves 

 (Fig. 206, 2). Colour in life purplish-violet. Reaches a size of 

 ca. 60 mm. length. 



Biology and development unknown. 



In British seas this species is know^n only from the cold area 

 of the Faroe Channel, where it w^as first discovered (half-way 

 between Shetland and Faroe), in 1150 m. depth, by the 

 " Porcupine." Also found there by the " Knight Errant ". The 

 species is elsewhere distributed all over the cold area of the 

 Norwegian sea, from N. of Iceland to Spitzbergen and the Kara 

 Sea, in depths of ca. 225-2450 m. 



