386 



HIROSHI OHSHIMA : 



has given rise to the connective tissue and the musculature of the 

 body-wall. 



The old doliolaria begins to sink to the bottoTi hand in hand with 

 the degeneration of the ciliary bands and the formation of the calcareous 

 deposits. The deposits make their first appearance at three places, i.e. 

 at the base of each tentacular canal, in the wall of the madreporic 

 vesicle, and in the integument of the posterior part of the body. 



Pentactula. 



This stage may be reached as early as on the fourth day, and is 

 characterized by the presence of five branched tentacles, which now 

 come to lie at the anterior end of the body owing to the gradual 

 diminution of the preoral lobe. The ciliary bands have totally dis- 

 appeared. The stomodanim breaks through and communicates with the 

 anterior end of the gut, the latter showing the characteristic coil and 

 the enlargement at the midgut. The anus is now open and is subdorsal 

 in position 



The pore-canal which connects the madreporic body with the 

 exterior is still visible during the early part of this stage, but is total- 

 ly obliterated in an old pentactula. The tentacles give out one or two 

 blunt branches, and the paired primary pedicels stand very- near to 

 the hind end of the body. The calcareous deposits of the integument 

 are represented by delicate perforated plates devoid of the spine and 

 knobs characteristic of the plates of the adult of this species. 



The larva creeps on the bottom and grows. 



Young. 



The stage which follows the pentactula may be called young. 

 Hand in hand with a remarkable increase in body size there appear 

 new tentacles and pedicels, and the rudiments of the respiratory trees, 

 etc. It will be superfluous to give further accounts in the presence of 

 Ludwig's observations on Cucumaria piatici. But one point may here 



