84 T. KOMAI : STUDIES ON TWU ABERRANT CTENOPHORES 



I have met with some egg-cells of very "large sizes lying outside of the 

 ventral epidermis (fig. 14), and others just about to be liberated through 

 it. Perhaps this shows nothing more than an artefact, yet it apparently 

 forecasts the fact that the eggs are laid outside through the ventral 

 epidermis. Moreover, many egg-cells may be found in the epidermis 

 of the parts between the meridional canals, and it is almost impossible 

 to imagine the falling of those cells into the lumen of the canals. In 

 any case, the occurrence of the egg-cells in the ectoderm is quite 

 unique in the Ctenophora — evidently, this feature has developed in relation 

 with the characteristic mode of life of Gastrodes. But, it is not very 

 striking that, such small individuals, less than 3 mm. in body diameter, 

 show very large egg-cells, since in certain ctenophores a peculiar mode 

 of reproduction called dissogony is known to occur, where minute 

 individuals can develop eggs and sperms precociously (Chun, '92). Both 

 KoROTNEFF ('8<S, '91) and Heider ('93) have observed egg-cells in 

 Gastrodes and recognized their situation in the ectoderm. 



In spite of the fact that the egg-cells were found in all individuals, 

 no sperm-cells, neither mature nor of any developing stage, could be met 

 with. This observation makes it possible that, the parasite propagates 

 parthenogenetically, which opinion seems to be taken also by Korot- 

 NEFF ('88). This author, however, gives in his later work ('91) that, he 

 observed sperms in the endoderm of one small specimen. But, judging 

 from his figure and description of the alleged sperms, they seem to be 

 nothing more than blood-corpuscles of Salpa taken up by the endodermal 

 cells. My examinations of a series of specimens of various sizes have 

 revealed no figure suggesting of the existence of sperms whatever. 



B o dy P are nc hy m e . 



The body parenchyme contains but small quantity of cellular 

 elements. Relatively numerous isolated cells showing some plasmic 

 processes are found under both the dorsal and the ventral epidermis. 

 The area between ribs is traversed by fibres running horizontally (PI. 8. 

 fig. i). The fibres arc muscular in nature without doubt; they show 

 branchings as in ordinary ctenophores (PI. 9, fig. 8). 



Developmental Cycle. 



Heider (1893) assumes that, the entrance of Gastrodes into the 



