WOUND CLOSURE AND POLARITY IN METRIDIUM 465 



more than one half during eight hours of watching. There were 

 shallow longitudinal wrinkles in the wall, but the distal end had 

 a more rounded outline than the proximal one. After the return 

 to normal sea water (seven to eight hours after the cutting), the 

 distal end became smooth and rounded, as in the normal closure 

 of the distal end of an excised fragment. Some fragments were 

 taken from the chloretone solution and fixed. Conditions found 

 in the sections of these fragments are not different, as regards 

 distal ends, from those described for the attached stump in chlore- 

 tone. The proximal end of the pieces in chloretone is strongly 

 wrinkled longitudinally and the walls are very deeply inrolled. 

 Except for the extent of the inrolling, no difference exists between 

 the closure of a proximal end in normal sea water and in chlore- 

 tone. 



In another series of experiments thirty-six tentacle fragments 

 were sectioned at certain intervals after excision, to corroborate 

 the seeming closure of the distal ends and to see if the proximal 

 ends remained open. In these fragments, as observed alive in a 

 watch glass, some proximal ends were open, but many seemed 

 closed. Eleven fragments lived in watch glasses for two days 

 after excision, when they were fixed; the remaining twenty-five 

 were fixed after four days. 



Sections show that the distal ends of all but one were structur-» 

 ally closed. This one had both ends open before fixation and 

 cellular debris streamed from either end. It was evidently in a 

 state of disintegration. Twenty of the thirty-six proximal ends 

 were open, ten were obviously closed, and six doubtfully so. Four 

 of the tentacles, taken from a large animal, were larger than the 

 others, measuring 20 mm. in length and 2.5 mm. in diameter at 

 the base. Size, however, does not seem to be a factor involved; 

 for of the four larger tentacle fragments, two were structurally 

 closed. The ten closed proximal ends show, in the sections, a 

 much stronger inrolling than any distal end (fig. 7) . The walls 

 of the proximal ends are brought close together before changes in 

 the thickness and relative position of the layers occur. At the 

 distal end, the cell layers of the very small region of union (co'jct., 

 fig. 8) are thin and the cells have no walls or are irregular in shape. 



