ECHINOIDEA 



349 



recorded also from S.W. of the Rockall Bank (" Porcupine "), 

 but it is impossible now to decide whether the " Porcupine " 

 specimen belonged to this or the following species, the specimen 

 having apparently been lost. Bathymetrical distribution, 1520- 

 3220 m. 



2 . Echinosigra pa radoxa Mrtsn . ( Fig . 210.) 



Differs from the preceding species by its much longer 

 and more slender neck : also the middle part of the body more 

 swollen, the posterior part again narrowing into what might 

 almost be termed a tail. The labrum and the adjoining ambul- 

 acral plates very long ; the second plates of these ambulacra, 



^ 



1 2 3 



Fig. 210. — Echinosigra jmradoxa. x 1-5. (After the " IngolJ " 



Echinoidea, ii.) 



1. Side view. 2. Dorsal. 3. Ventral side. 



which join in the mid- ventral line behind the labrum, with a long 

 dividing line in the anterior edge and a shorter one in the posterior 

 edge ; these lines, however, do not join, the plates being thus not 

 really subdivided. Anal snout curved slightly upwards. Peri- 

 proct slightly sunk. Only two genital openings. Spines and 

 pedicellariae as in the preceding species, only the rostrate with 

 the valves slightly different, with more serrations (Fig. 209, 4). 

 Colour in life probably white ; the test fairly transparent. 

 Largest size recorded, 37 mm. in length. 



Development unknown. The remarkable shape, in fact the 

 most extreme of all Echinoids known, must necessarily confine 

 this species to the perfectly quiet and soft deep-sea bottom, as 



