326 



ECHINODERMS OF THE BRITISH ISLES 



thus forming its food. Development unknown, but the large, 

 yolky eggs indicate that it has direct development, without a 

 pelagic larval stage. 



In British seas this species has been found only in the Faroe 



Fig. 189. — Brisaster fragilis. (1. From Danmark's Fauna.) 



1. Specimen with the spines preserved, showing the peripetalous and lateral fascicles. 

 2. Naked test. Both from above ; nat. size. 



Channel, N. and W. of Shetland, 720-900 m. (" Porcupine "). 

 It is elsewhere distributed along the Norwegian coast, from 

 Bergen to Finmark, S. and W. of Iceland, and from the Davis 

 Strait to Florida. Bathymetrical distribution ca. 65-1300 m. 



II. Family Spatangid.e 



Ambulacra on upper side of test petaloid, widened, and more 

 or less sunk ; first plate of posterior interambulacrum developed 

 into a prominent lip, partly covering the mouth and the trans- 

 versely elongate peristome. A closed subanal fasciole present. 



Three genera represented in the British seas ; two more 

 genera are represented in the Mediterranean and the N.E. 

 Atlantic, namely Brissus Leske and Plagiohrissus Pomel. Of the 

 former, the species Br. brissus (Leske) (Sj^n. Brissus unicolor 

 Klein) is distributed from the Mediterranean to the Cape Verdes, 

 the Azores, St. Helena, and the West Indies, in depths of ca. 

 10-240 m. ; of the latter, the species Plagiohrissus Costce (Gasco) 

 (Syn. Metalia Costce Gasco) is known only from the Mediter- 

 ranean, but may well be expected to extend also to the Atlantic ; 

 it is known from depths of ca. 25-150 m. There is hardly any 



