A454 WwW. A. HASWELL. 
um die Epithelzellen verlaufen, nach aussen und seitlich von 
den letzteren, nach innen noch zum Theil vom Hautmuskel- 
schlauch begrenzt werden.” That these canals are not, as it 
is here suggested they may be, formed as the result of the 
action of reagents is rendered evident by their conspicuous- 
ness in living specimens, But even if we had not that 
evidence, their arrangement in such a preserved specimen as 
that from which fig. 29 was drawn, following as it does a 
regular system, appears to me to be quite convincing. In 
such a view as that represented, which is a small part of what 
extends over the entire surface, main channels are traceable, 
giving off branches, the size of which is, on the whole, very 
uniformly regulated by that of the vessels from which they 
are derived. To bring this about, cells of a variety of sizes 
and of innumerable shapes are fitted in together in a highly- 
complicated manner. 
In Schneider’s ‘ Lehrbuch der vergleichenden Histologie 
der Thiere’ there is a figure (fig. 317) of the epidermis of 
Planocera folium, which is given, rather strangely, to 
illustrate the structure of Dendrocelum lacteum. In 
this is shown an intercellular space, which is not unlike those 
we are considering, but is made to perforate the basement 
membrane. In the text the author says: 
“ Zwischen den Deckzellen finden sich oft deutlich hervor- 
tretende Intercellularliicken; auch wurden in den Zellen 
vieler T'urbellarien (Sekera, Bohmig u. a.) helle aufsteigende 
Kanialchen beobachtet die einerseits die Grenzlamelle durch- 
setzen und mit dem Hnchym zusammesshingen andererseits 
auch nach aussen ausmiinden Konnen. Die Kanale nehmen 
oft den character weiter vacuvlen an. Sie sind wohl als 
Lymphkanalchen zu betrachten” (p. 296). 
Here it is to be observed that it is the first clause of the 
first sentence only that refers to intercellular spaces. The 
rest deals with Sekera and Bohmig’s “ wasserklare Raume,” 
which have never been shown to have anything to do with 
the intercellular spaces. ‘The figure, unfortunately, seems to 
combine two quite distinct spaces—an intercellular space and 
