76 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



Another peculiar phenomenon presents itself in these cells. The 

 distal part of each cell becomes separated off from its body by what 

 appears to be the formation of a transverse cell-wall (Fig. 31, c-d). I 

 have found the ends of these cells quite separated off in some series. 

 The formation of the walls seems to begin as a thickening at the sides 

 of the cells, and a section through this region, transverse to the cells, 

 would appear like Fig. 30. The dots in the centers of the polygonal 

 areas of this figure are the centrad continuations of the cilia to be 

 described below. As already remarked in describing the endoderm 

 of the ampulla, I believe we here have another place of origin of 

 the "floating cells. 1 ' The secretion just described moves into the 

 distal parts of the cells prior to their separation (Fig. 31). In some 

 series I could see these secretion bodies much more numerous within 

 the distal ends of the cells than in Fig. 31. 



As will be seen in Fig. 31, each of the endoderm cells of the 

 tentacles has a flagellum that extends into the lumen of the tentacle. 

 Each flagellum has a thickening just within its cell, which may be 

 regarded as a basal body. From this basal body, again, a small fiber 

 extends centrad into each cell. It does not appear that the flagella 

 are thrown off with the distal parts of the cells ; at all events, I never 

 found them connected with any of the floating cells except in a few 

 doubtful instances. 



What I have said for the endoderm of the tentacle of Charybdea 

 applies equally to Tripedalia. 



Glaus, in his figure of a transverse section of a tentacle of C. 

 marsupialis shows the endoderm as cubical. I cannot explain why 

 there should be such a difference between the endoderm of the 

 tentacles of C. marsupialis and that of the tentacles of C. Xaymacana 

 and Tripedalia cystophora. Glaus does not describe the endoderm in 

 detail. 



The endoderm cells of the pedalia of both Charybdea and 

 Tripedalia are cubical and possess flagella, basal bodies, and centrad 

 continuations, quite like those I have described for the endoderm cells 

 of the ampulla. The double nature of the basal bodies and the centrad 

 continuations is, however, not so evident. A secretion I did not find. 

 Histologically, therefore, the endothelium of the pedalia corresponds 

 rather with that of the ampulla, and that of the tentacles with that 

 of the peduncle of the clubs. 



