146 



TIIEEE CRUISES OF THE " BLAKE. 



into joints alternately long and short ; the longer ones white, 

 hollow, and calcareous, and the shorter ones horny brown. 

 We should also mention Primnoa Pourtalesii (Fig. 458), a 

 plumose gorgonian with regularly pinnate branchlets all in one 

 plane. To this genus belongs also the huge bush coral Primnoa, 



Fig. 45S. — Primnoa Pourtalesii. £. (Verrill.) 



which grows to the height of man, and has an axis as thick as 

 a man's leg. 



Many of the gorgonians are beautifully phosphorescent when 

 brought to the surface, and their closely clustered branches, as 

 in Calyptrophora (Fig. 459) are the abode of hosts of Crustacea, 

 annelids, mollusks, and echinoderms, which find shelter there 

 from their enemies. 



The Actinidse, or sea-anemones, so common in shallow water, 

 are represented by a number of species in our deep waters ; 

 many of them are finely colored, some of them developing a 

 peculiar base adapted to soft bottoms, representing perhaps, as 

 has been suggested by Verrill, a primitive type from which the 



