57« 



TAKU KOMAI : 



outer parts but expand terminally into an ampulla-like or somewhat 

 irregular-shaped swelling. The number of the invaginations fluctuates 

 between 7 and 1 3 to each subtentacular, and between 4 and 8 to each 

 subpharyngeal, canal. Quite frequently, the invaginations, but especially 

 their blind terminal swellings, are seen to contain a large quantity of 

 spermatozoa ; so that it is evident that they serve as sperm-receptacles. 

 Where and how the spermatozoa meet the eggs in fertilization is not 

 clear, but possibly they may make their way through the intervening 

 tissues and reach the eggs in the ovaries. 



Eggs. — As already indicated the laid eggs are found under the 

 mother animal, agglutinated together by a gelatinous substance, instead 

 of being set free as pelagic objec's as in ordinary ctenophores. There 

 they undergo development and reach the stage in which the embryo 

 is completely formed. The number of eggs carried by an individual 

 in the said position is generally from io to 50, but may sometimes be 

 as large as 200. All those under one and the same mother individual 

 are nearly in the same stage of development. 



Newly laid eggs (Fig. 1) show essentially the same structure as those 

 of pelagic forms. A distinct membrane envelops each egg. Directly 

 within it is a rather narrow space which appears to be filled with a thin 

 gelatinous substance. The size of eggs varies but little. The entire egg 

 as surrounded by the membrane measures in average diamètre about 

 0.3 mm., and the egg-body proper without the membrane 0.25 mm. 



As in ordinary ctenophores, the egg-body consists of the ectoplasm 

 (ec) presenting a finely granular appearance and of the endoplasnt (en) 

 showing an alveolar structure. The former occupies the entire periphery 

 in a layer, while the latter in the central parts constitutes by far the 

 greater portion of the entire eg^-body. Two polar bodies (p) are 

 frequently seen, lying on the surface of the egg-body ; they are either 

 spherical or more or less flattened. More rarely, there occur three 

 polar bodies lying side by side, appare ntly as the result of division of 

 the first polar bady. 



