268 OTT. [Vol. VII. 



Rhabdocoels each cell of the parenchyme is made up of a Geriist- 

 substanz and a Saftplasma. The Geriistsubstanz forms the 

 periphery of the cell and is also arranged in a network through- 

 out the cell. The Saftplasma fills the spaces bounded by the 

 network within the cell. The peripheral layers of Geriist- 

 substanz of the single cells come to be interrupted, thus destroy- 

 ing the cell boundaries, allowing the Saftplasma of adjacent cells 

 to mingle, and making the general network of the parenchyme. 

 " Das Geriist Werk des Parenchyme ist die Summe der Zellge- 

 ruste." 



In both groups of the Dendrocoels and probably in some Rhab- 

 docoels vacuoles are formed in the developing parenchyme. 

 These vacuoles are inter-cellular in the Triclads and intra-cellu- 

 lar in the Polyclads. Thus in the Polyclads the network which 

 partly surrounds each vacuole is made up of the periphery of the 

 cell in which the vacuole was formed. In the Triclads each 

 vacuole is surrounded by a network which is composed of the 

 whole of the originally adjoining cells. 



In conclusion, Bohmig ('90, p. 206) says, " Die Trennung des 

 Parenchymgewebes in Bindegewebsbalken und Bindegewebszel- 

 len (V. Graff) muss aufgegeben werden, wie auch lijima fiir die 

 Tricladen und Lang fiir Polycladen betont hat." 



From the study of both the living Stenostoma leiicops and 

 from sections (pp. 265-267) the parenchyme is seen to be made 

 up of two substances, — a network (Bohmig's "Geriistsubstanz "), 

 and a perivisceral fluid (B5hmig's "Saftplasma"). 



The spaces enclosed within the network are connected with 

 one another by the openings through the network, and the peri- 

 visceral fluid is a continuous mass throughout the parenchyme, 

 as may be seen in sections and in the living worm. In sections 

 a break in the network is occasionally seen, so that the contents 

 of adjacent spaces are continuous. In the living worm the 

 perivisceral fluid which is contained in the spaces of the network 

 could not flow from one part of the parenchyme to another 

 (p. 265) unless there were continuous passage-ways from one 

 space to another. 



In the parenchyme of worms which have been fixed with 

 corrosive sublimate the cells may be seen in many places to be 

 massed together, while in other places they are separated a 

 short distance and are connected by their processes into a net- 



