RICHARD L. WOOD 61 



Fig. 7. Mesogleal relationship of epidermal muscle processes (top). The 

 muscle fibers extend irregular processes into the mesoglea, some of which 

 traverse the mesoglea completely (center). Those which traverse the mes- 

 oglea may abut against similar processes from the gastrodermal cells (bot- 

 tom). C, cnidoblast; M, muscle. 7,000X. 



for light microscopy and for electron microscopy, the mesogleal 

 sm'face of epitheliomuscular cells is plicated and irregular. Fre- 

 quently the mesoglea is completely traversed by narrow cytoplas- 

 mic processes (Fig. lb, circle; Fig. 7). These connections were seen 

 and illustrated by Hadzi in 1909 (3) but have not captured the 

 attention of morphologists again until rather recently. They extend 

 from epithelial cells situated in both layers. Within the mesoglea, or 

 at one epithelial surface, the processes may abut against the oppo- 

 site epithelium either along a fairly broad surface or in a very 

 limited area (Figs. 7,8). So far as has been observed, the processes 

 extending across mesoglea represent regions of contact between 

 the two epithelial layers but not cytoplasmic continuity. Two dis- 

 tinct plasma membranes have always been seen although a reduc- 

 tion of the spacing between the apposed membranes is often evident. 

 In fact, the typical 150-200 A separation may essentially disappear, 

 as is illustrated in Figure 8. 



