190 



are no ciliated epaulettes and pedicellariae in S. griseus, but the epidermal 

 vibratile lobes are far less developed. With the appearance of the amniotic sac 

 by the 5th-6th day of development, the basal and secondary basal rods elon- 

 gate distally and intertwine. Both pairs of inner transverse rods begin to 

 reduce. Few granules of red pigment appear at the arm tips. The larva reaches 

 a length of 900-1000 |im. Like the larvae oi E. parma, the pluteus III stage 

 acquires a light green color when placed in 70° alcohol (Figure 143). 



Ecology 



Larvae of S. griseus begin to appear in the plankton of Vostok Bay in 

 September when the water temperature in the surface layer is 17°C. The first 

 settling urchins were obtained in the laboratory by mid- September. 



■al 



Figure 143: Scaphechinus griseus. Pluteus III stage. 

 Legend same as in Figures 109 and 139. 



ECHINOCARDIUM CORD A TUM (PENNANT) 

 (Loveniidae) 



Mature eggs vary in diameter from 90 to 100 )im. The eggs are not pig- 

 mented. The blastula develops 28 hrs after fertilization and the gastrula after 

 42 hrs at a temperature of 20-21 °C. The early pluteus, formed on the 3rd 

 day of culturing, exhibited a large number of granules of red pigment. The 

 bright color of the larvae of this heart urchin distinctly distinguishes them 

 from the larvae of other urchins that may occur concurrently in the plankton. 



