48 ANDREWS. 



there is more apt to occur this phenomenon which is very 

 characteristic of ectosarcal formation, and which has almost un- 

 bounded possibilities in an evolution of protoplasmic structures, 

 as will be shown further oxi} and in still another publication 

 now in preparation for press. I speak of what I shall call 

 stnicUiral redttctioji, that is, a redistribution of the elements in 

 an existing structure so as to group them into a new and finer 

 foam structure. The vesicles of the existing structure become 

 quickly more minute, and should subdivision continue, yet finer 

 and finer, being always increasingly small towards that outer 

 side or portion of the area which is peripheral as to the mass. 

 Structural reduction takes place in a number of ways. The 

 alveoli of Biitschli's structure were seen at times to be cut in 

 two by constriction, or pinching off, just as a contractile vacuole, 

 or as the oesophageal cleft of Vorticellidae divides. Sometimes 

 the interalveolar substance spins itself into and across fluid 

 inclusions ; sometimes there seems to be local relaxation of 

 interalveolar or continuous substance, causing redistribution 

 of alveolar inclusions. 



But however it may be done, the fact is certain that it is 

 done, and that in most cases of ectosarcal formation there is 

 more or less structural reduction and reorganization of the two 

 groups of elements, which may or may not extend itself to the 

 interalveolar structure where it is visible by change of the 

 optical quality of this substance ^ or again may be confined to 

 this alone. 



The amount of such reduction varies with the circumstances 

 of formation, or even, to all seeming, irrelevantly to these. 

 Where large areas of new ectosarc are brought into direct 

 peripheral contact with the water, or general environment of 

 the mass, there is more structural reduction than where the 

 outflow is checked by presence of existing ectosarc in a thick 

 layer. It was the optical appearance of these phenomena as 

 seen with powers too low to resolve structure, which gave earlier 

 observers an idea that the substance became coagulated on 

 contact with the water. As a matter of fact, ectosarc may be 



1 See Selection of Environment. 



2 See Striation. 



