No. 3.] STUDY OF STENOSTOMA LEUCOPS O. SCHM. 269 



work. In the parenchyme of worms which have been fixed in 

 chrom-osmic-acetic acid large cells may be seen connected with 

 the network. This network resembles the cells very much, 

 both as to the fineness of its granules and as to the amount of 

 stain that it takes. 



The above facts indicate that, as Bohmig states for Triclads 

 and as he surmises for some Rhabdocoels, the network of the 

 parenchyme of Stenostoma leiicops is formed by the fusion of 

 individual cells, which are connected by longer or shorter branch- 

 ing and anastomosing processes (Geriistsubstanz) and are sep- 

 arated by inter-cellular vacuoles. 



Alimentary Canal. 



The alimentary canal of Stenostoma lencops occupies the 

 posterior three-fourths of the body cavity of a single individual. 

 In some cases the posterior part of the alimentary canal (intes- 

 tine) as seen in the living worm is in contact laterally with the 

 integument, while in others there is a slight space (parenchyme) 

 left between it and the integument. In the majority of cases 

 the intestine does not reach to the posterior end of the body, so 

 that there is, in the living worm in optical section, a clear trian- 

 gular space left between the posterior end of the alimentary 

 canal and the posterior body wall. 



In other cases the posterior end of the intestine is in contact 

 with, or a very slight distance from, the posterior body wall. 

 These differences in the relation of the alimentary canal to the 

 body are due to the state of contraction of the animal, to its 

 stage of development, and also to the degree of distension of 

 the alimentary canal. 



In an individual from which a bud has recently separated the 

 alimentary canal reaches to the posterior end of the body. 

 Before this separation takes place the lumen of the intestine is 

 obliterated by a constriction between the bud and the mother, 

 and the opening leading to the bud is thus closed. The bud 

 separates from the mother before a similar constriction of the 

 integument has travelled far enough to entirely close the ends of 

 the divided body wall tube. It thus happens that for a time 

 the posterior end of the intestine of the mother is left exposed. 

 After the bud has become free the posterior body wall of the 



