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DR. IWAJl ÏKEDA 



roofing the lower cavity. The septal structures separating the two 

 hydranth-cavities as also that which separtes the lower hydranth-cavity 

 from the hydrocaulus-cavity, are essentially the same as in Tubvloria 

 and Branchiocerianthus. The upper septum is supported interiorly by 

 a membraneous sheet of the mesoglcea arising from that of the body- 

 wall just inside the row of proximal tentacles. The upper surface of 

 the septum is lined by the glandular endoderm, while the lower 

 surface, i. c, the roof of the lower cavity, is made up of the parenchy- 

 matous endoderm. The latter projects in the middle of the upper 

 surface of the septum in the form of a small protuberance. The lower 

 septum, or the perforated membrane of Torrey, and its mesoglceal 

 support are far less developed than the upper septum and its support- 

 ing membrane respectively. The upper surface of the septum is lined 

 by a thin sheet of pacenchymc. Thus, both the channel and the lower 

 hydranth-cavity differ from those of C. nutans, as described by All- 

 man in being lined entirely by parenchymatous, instead -"of glandular, 

 endoderm. In the present species the glandular endoderm is, so far as 

 concerns the hydranth, confined to the hypostomal cavity and its gonoso- 

 mal prolongation (fig. ^,gs.). The glandular endoderm forming the floor 

 of the hypostomal cavity is always radially folded so as to produce 

 a large number of ridges arranged with some regularity in relation to 

 proximal tentacles. 



Apparently peculiar to the present form is a structure, which is 

 found in the hypostomal endoderm and which produces certain free 

 cells (Fig. 3, /. gl.). It is situated between the gonosomal and tenta- 

 cular (proximal) rows in the form of a narrow ring measuring about 

 o. II mm. in breadth. The zone is easily detected in sections as a 

 remarkably thin and highly stainable epithelium. Under a high power 

 of the microscope one finds that the .epithelium here consists of a 

 compact mass of polygonal cells of a remarkably small size (7 /i 

 in diameter) and having finely granular and highly staining cytoplasm. 

 Those cells lying in contact with the mesogloea are somewhat taller 



