107 



Astriclypeus Manni Yen-ill. ') 



PI. IV. Fi. 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 27lh of 

 June in getting a good culture, the larvae developing 

 normally and metamorphosing. 



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

 mucilaginous coat. About the first developmental processes 

 I have no notices; at the age of 1 1 hours the embryos 

 were in the process of gastrulalion, the blastocoel being filled 



Fis.. t:s. Egg of 

 Manni. /,. 



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. 44. Skeleton of the larva of As/ricli/pi-us Manni. 2SO /,. A. from tin- ventral si<lc: 



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



') In the "Preliminary Notice on Hie Development of some Japanese Kehinoderms 

 (Annot. Zool. Japon. VIII. 1914. p. .VI 7) I designated this species as "Mellita japouim". 

 having wrongly got it into my mind that there existed a Mellila japonica; that paper brini; 

 written at sea, I had, of course, no access to (literature so that I could not then correct I In- 

 wrong idea. 



14* 



