]48 THE DEPTHS OF THE SEA. [CHAP. iv. 



arranged vertically, and this peculiar tissue forms a 

 complete sheath surrounding a pulpy mass of gra- 

 nular horny and sarcodic matter which fills the in- 

 terior. In this inner spongy substance sheaves of 

 similarly-shaped spicules are likewise arranged ver- 

 tically, but much more loosely ; and the projecting 

 scales forming the head of Thecophora ibla are formed 

 by the projecting ends of such sheaves. Among 

 echinoderms, Ophiacantha spinulosa was one of the 



FIG. 24. Thecophera ilia, WYVIU.E THOMSON. Twice the natural size. (No. 7f,.) 



prevailing forms, and we were greatly struck with 

 the brilliancy of its phosphorescence. Some of 

 these hauls were taken late in the evening, and the 

 tangles were sprinkled over with stars of the most 

 brilliant uranium green ; little stars, for the phos- 

 phorescent light was much more vivid in the younger 

 and smaller individuals. The light was not constant, 

 nor continuous all over the star, but sometimes it 

 struck out a line of fire all round the disk, flashing, 



