124 A.OKA. 



cells with centrally situated small nuclei. This cellnlar envelope 

 completely encloses a granular mass of protoplasm Qpyin. mass.) in 

 which are scattered minute nuclei. These nuclei measure only 

 0.001x0.003 mm. in average, and are thus several times smaller 

 than the nuclei of body tissues. They are very flat witli their plane 

 parallel to that of the statoblast. 



The granular contents and the cellular envelope form the 

 essential part of the statohlast, while the chitinous cnpsnle, the an- 

 nul iis and the marginal spines nre all accessory organs for its 

 preservation and distribution. 



2, Development of the Statoblast. 



The knowledge of the origin of statoblast is certainly of vital 

 importance in determining the true nature of this gennnule-like 

 body, but in the rather scanty literature on this subject the state- 

 ments given are widely different from one another. As to my own 

 observations, I have seen in tlie lumen of the funiculus sometimes a 

 single cell and at other times a loose group of two or more cells, 

 representing the earliest st;!ges of development of statoblasts. They 

 are refund in outline, and each supplied with an oval nucleus, j^either 

 in size nor in general appearance do they perceptibly differ among 

 tliemselves, ov from those of neighboring tissues. This circumstance 

 deprives me of all grounds to share Verworn's view that the increase 

 of cells is (hie to continued division of an originally single cell. This 

 author sums up the earliest steps in the development of a statoblast 

 in the following words : An einer bestimmten Stelle des Funiculus 

 vermehren sich die Epithelzellen desselben zu einer kleinen Auf- 

 schwellung and drängen dadurch gegen das Lumen. Eine Zelle davon 

 tritt in das Lumen hinein and wird zur Eizelle, während die anderen 



