107 



Astriclypeus Manni Vemll.i) 



PI. IV, Fig. 1. 



This species, which occurs in quite shallow water, buried in the sand, 

 near the Biological Station at Misaki, was found to have ripe sexual 

 products in June (1914); fertilization was undertaken on .:.■.-. 



the 2nd, but did not result in a good culture. After some 

 more unsuccessful attempts I succeeded on the 27th of 

 June in getting a good culture, the larvae developing 

 normally and metamorphosing. 



The egg (Fig. 43) is surrounded by a strongly pigmented 

 mucilaginous coat. About the first developmental processes 

 I have no notices; at the age of 14 hours the embryos 

 were in the process of gastrulation, the blastocoel being filled with 

 mesenchyme cells; the ectoderm is thick, especially at the oral end. After 

 three days the larvae had already nearly reached the full shape, the 

 posterodorsal arms having been formed. At the age of 6 days the meta- 

 morphosis was beginning, and after another week some of them had 

 completed the metamorphosis, while other specimens were not yet so far 



Fig. 43. Egg of 

 Astriclypeus 

 Manni. *Vi- 



Fig. 44. Skeleton of the larva of Astriclypeus Manni. ^"U- A. from the ventral side; 



B. side view. Letters as in fig. 20. 



1) In the "Preliminary Notice on the Development of some Japanese Echinoderms" 

 (Annot. Zool. Japon. VIII. 1914. p. 547) I designated this species as "Mellita japonica", 

 having wrongly got it into my mind that there existed a Mellita japonica; that paper being 

 written at sea, I had, of course, no access to litterature so that I could not then correct the 

 wrong idea. 



14* 



