SALENIA MILIARIS. 



51 



serrations and spinules of the primary radioles are proportionally very lar^e 

 as compared to the diameter of the shafts/ 



In a specimen of 5 mm. (Pis. 16, figs, y, ^; 17, figs. ^ o) the primordial 

 plates have been resorbed and the first pairs of plates are m contact with the 

 actinal system in all the interambulacra, Fig. 82. There are nine to ten 

 pairs of ambulacral plates with five to six pairs of interambulacral plates, the 

 sixth being a small plate or merely indicated in the interambulacral areas. 



10 mm. 



Fig. 84. Salenia miliabis. 



In a specimen of 8 mm. (Pis. 16, figs. S, 4; 17, figs. 6, 7), with fifteen to 

 sixteen pairs of ambulacral plates, the first interambulacral plates are still 

 in contact with the actinal system. Fig. 83, the sixth pairs of interambulacral 

 plates are fully developed, and the seventh is composed of smaller plates in 

 all the interambulacra. 



In a specimen of 10 mm., Fig. 84, the conditions since the preceding 

 stage have changed but slightly (Pis. 16, figs. S, 6; 18, figs. 1, 2), the 

 seventh pair of interambulacral plates being somewhat more advanced. 



^ See the fimbriated spines of a young S. varispina, " Blake " Echini, PI. VI. fig. 1. 



