30 T. KOMAI : STUDIES ON TWO ABERRA.NT CTENOPHORKS 



corpuscle (PI. 4, fig. 16) varies a great deal in size and in the kind of 

 inclusions. In PI. 4, fig. 16 e-h are represented some of the corpuscles 

 in natural state, while a-d shows them in fixed and stained condition. 

 They are sometimes provided with a nucleus and rarely even with two 

 nuclei (a-c), which have come without doubt from the matrix cells. 



Besides the method of formation of the corpuscles just mentioned, 

 there seems to be another by which larger bodies such as figured in 

 fig. 16, i are produced. This latter method consists in the parts of the 

 vacuolated epithelium loaded with foreign objects being simply constricted 

 off from the matrix, as Abbott ('07) previously remarked. Although 

 practically any vacuolated part of the epithelium may perform intra- 

 cellular digestion, that of the dorsal wall of the tentacular canals appears 

 to play the most important part of the function. The epithelium in that 

 part has by far greater thickness than elsewhere and contains usually a 

 very large quantity of foreign objects. Colloblasts may often be met 

 with among the inclusions in that part; evidently, they have been 

 caught in together with the food matter. The palisade epithelium on 

 the dorsal side of the subpharyngeal and subtentacular canals also seems 

 to digest food material intracellularly, as may be judged from the 

 inclusions. 



As regards the physiological significance of the process described 

 above, it seems to be reasonable to regard the process to be a sort of 

 excretory function. Anyway, it is certain that, by the production of the 

 corpuscles, the indigestable parts of intracellularly ingested food are 

 removed from those cells. At the same time, it is not impossible that, 

 certain waste products of metabolism are ejected by means of the 

 corpuscles which contain vacuoles without any solid inclusion whatever. 

 Certain as the occurrence of the intracelluler digestion in the animal, it 

 seems probable that, that does not constitute the sole process of digestion, 

 but this is effected in part also outside of the cells. The freqyent 

 occurrence of the remains of crustacean skeleton in the cavity of the 

 canal system and especially in that of the pharynx as mentioned above, 

 stands in favour of this view. It seems to me that, the process (if the 

 digestion begins in the pharyngeal cavity and is brought to a finish 

 intracellularly in the vacuolated epithelium of the endodermal parts. 



Before closing the accounts on the gartro-vascular system, I 

 may point out some discrepancies existing between observations of 

 previous writers and myself. According to Aubott ('07), tiiere should 

 be a pair of pcrradial canals which are given out from the infundibulum 



