E. W. BERGER ON THE CUBOMEDUS.E. 73 



nuclear division within these also receives an explanation. Some 

 nuclear matter can usually be observed in the floating cells. 



The Endothelium of the Peduncle. The endothelium of the peduncle 

 consists of flagellate columnar cells (Fig. 27, upper half). The cells 

 are vacuolated at their bases like some of the cells of the ampulla, 

 and contain a comparatively large nucleus with nucleolus. The 

 flagella are long and slender, quite like those described for the cells 

 of the ampulla, except that there is only one to each cell. The basal 

 bodies of the flagella are of a peculiar shape. They may be described 

 as a bent spindle, continuous at their distad ends with the cilia and 

 at their centrad ends with a fiber that can be traced quite to the 

 neighborhood of the nucleus. I could not trace these fibers into the 

 basal parts of the cells, except in one instance, and I could not be 

 sure of that (Fig. 27a). 



Another interesting observation in connection with the basal 

 bodies is that they are bent in one direction on one side of the canal 

 and in an opposite direction on the other side. In Fig. 27, which 

 represents a longitudinal section of the endoderm and the supporting 

 lamella of the dorsal (i. e. farthest from the eyes) side of the peduncle, 

 the distal ends of the basal bodies are bent towards the ampulla, 

 while on the ventral side they would be bent away from the ampulla. 

 This seems to suggest that the flagella move the contents of the 

 canal in one direction on the dorsal side of the canal and in an 

 opposite direction on the ventral side. Conant observed in living 

 material that bodies in the ampulla and the canal were moving 

 about, and that bodies within the tentacles were moving in opposite 

 directions at the same time. This last observation and the histological 

 facts just described, I believe, are mutually corroborative. Again, a 

 priori, we should expect some such mechanism as the one described 

 to bring about an exchange between the contents of the ampulla and 

 that of the stomach pockets. I have not as yet been able to demonstrate 

 a similar flagellate mechanism in the tentacles. Flagella and basal 

 bodies are present in the tentacles, but I could not determine that 

 the basal bodies had any definite arrangement like that shown in 

 Fig. 27. (See under tentacles.) I may add, yet, that the cells in the 

 canal of the manubrium have cilia, similar to the ones just described, 

 with large basal bodies, and with centrad continuations. Finally, I 

 am not certain but that these cells form buds at their ends quite 



