68 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



peduncle, where also a small tract is found under the endoderm. 

 (See preceding head, or Glaus 3 , and Conant 8b ). As already noted, 

 under the distal complex eye, I find only large nuclei to represent 

 the ganglion cells. By saying this, however, I do not wish to dispute 

 their ganglionic nature. The large multipolar ganglion cells I have 

 noted under the preceding topic. 



The Supporting Lamella. The supporting lamella is a continua- 

 tion, through the peduncle, of the jelly of the bell. It completely 

 surrounds the ampulla and the lithocyst, and also forms a partition 

 between them, so that, as already noted, the lithocyst becomes 

 completely surrounded by it. It also sends a partition ventrally 

 between the complex eyes (Figs. 7, 13). Its thickening to form a 

 support for the lens of the proximal complex eye has already been 

 noticed. I shall limit myself in the discussion of the supporting 

 lamella to the above short resume, since Schewiakoff gives further 

 detail. 



The Endothelium of the Ampulla and the " Floating Cells." The 

 ampulla is lined by a secreting epithelium. This is shown by the 

 large masses of a secretion within the bases of the cells, and by 

 smaller masses scattered in the central and more distal parts 

 (Figs. 7, and 27, lower half). The section of the cells is such in Fig. 

 7, that the bases of some (those nearest the supporting lamella) are 

 taken, the central nuclear region of others, and the tips of those 

 farthest from the supporting lamella. The section may be said to be 

 taken diagonally through the bases and central parts of some of the 

 cells, but owing to the curvature of the ampulla wall, through the 

 tips of others. The secretion is a colloid substance, staining yellowish 

 gray with iron-haematoxylin, blue with Lyons blue, and reddish 

 with borax-carmine. Sometimes darkly staining rods and fibers of 

 unknown origin could be seen within the larger masses of the 

 secretion (Fig. 7). These rods and fibers could also be seen in 

 spaces within the cells, from which the secretion had evidently been 

 dissolved. I think there can be no question but that the masses 

 described are a secretion. Many series, however, do not show it; 

 indeed, an examination of Conant's slides gave me little evidence 

 of a secreting function, though I could demonstrate it in his sections 

 both within the endothelium and also the floating bodies. The 



