324 ECHTNODERMS OF THE BRITISH ISLES 



It is a very fragile form, which must be assumed to live buried 

 in the soft deep-sea mud. Development unknown. 



In British seas this species has been found in fair numbers off 



7- u 



Fig. 186. — Hemiaster expergitus ; naked test, seen from above (I), from 

 below (2), and in side view (3). Nat. size. (After Th. Mortensen, 

 " Ingolf Echin., ii.) 



the west coast of Ireland C' Helga "), in ca. 940-1770 m. It is 

 further known from off the Norwegian coast (61° 40' N., 3° 11' E.) i 

 and S. of Iceland to the Azores and Cape Verde Islands, and 



Fig. 187. — Valves of globiferous pedicellarife of Hemiaster expergitus (1) 

 and Brisaster Jragilis (2-3). x 50. (After Th. Mortensen, '' Ingolf 

 Echin., ii.) 



1 and 2. From the inside. 3. In side view. 



from the Davis Strait to the West Indies, in depths of ca. 400- 

 3120 m. Also in the Pacific, as the form described from there 

 under the name of Hemiaster gibbosus A. Ag. seems to be indis- 

 tinguishable from H. expergitus. 



1 This locaHty seems ratlier extraordinary for an Atlantic deep-sea form 

 and may perhaps be due to erroneous labelling ; at least it may be regarded 

 as uncertain until the species has been found there again. 



