26 T. KOMAI : STUDIES ON TWO ABERRANT CTENOPHORES 



the two cavitves into communication along with the oesophagus. These 

 branches and canal are lined with an epithelium which is identical with 

 that of the oesophagus. Evidently, Chun ('So) has recognized the 

 oesophagus in the stomodaeum of ordinary ctenophores, contrary to 

 Mortensen's statement ('12). Thus, what Chun has called " Trichterlip- 

 pen" is to be identified apparently with the parts of the wall of the 

 oesophagus that show the large clear gland cells described above and 

 his " Trichterspalt " with the narrow passage between those parts. 



The oesophagus communicates dorsally with the infundibulum (PL 

 2, figs. 2, 4; PI. 3, fig. I, PI. 4, fig. 8; i), which forms the source of the 

 whole endodermal parts of the gastro-vascular system. It is placed 

 directly beneath the aboral sense-organ and is cup-like in shape, showing 

 compression in neither direction. It is lined with a low ciliated epithe- 

 lium, in which occur numerous nuclei arranged at very short and regular 

 intervals (PI. 4, fig. 8; i). The epithelium is very low on the roof of 

 the cavity; it becomes gradually taller towards the bottom, where it 

 goes into the oesophageal epithelium, the transition between the two 

 kinds of epithelia being rather definite. 



Directly from either sagittal side of the infundibulum, starts an 

 excretory canal (PI. 4, figs. 8, 14; ex. c), the part which can be identified 

 with the infundibular canal of ordinary ctenophores (PI. 2, fig. 3, tJtf. c) 

 being absent. Each excretory canal proceeds to the dorsal direction 

 and opens without branching to the exterior by the excretory pore 

 situated in the sagittal plane just outside the sense organ. Abbott ('07) 

 maintains that, the excretory canals "arise in such a position that along 

 the tentacular plane the lower one is to the right and the upper one 

 to the left of that plane" (p. 53). But I found of the canals that 

 both the starting point and the external opening lie right in the sagittal 

 plane of the body. The excretory canal is lined with a low ciliated 

 epithelium of the same character as that of the infundibulum for the 

 greater part of its length. The epithelium thins strikingly close to the 

 pore, even to an extent to become almost structureless and glassy in 

 appearance. 



In the surface view of living specimens (PI. 4, fig. 6), the excretory 

 canal shows through rather distinctly under the epidermis. The positions 

 of the excretory pores are indicated by a peculiar assemblage o{ granular 

 gland cells around a roundish or somewhat crescentic depression of the 

 epidermis within the aboial unpigmented area referred to before. 



The infundibulum sends off on either transverse side of its wall a 



