108 Macreay Memoriat Vo.Lume. 
After a Temnocephala has remained at rest for some time on one spot on the 
surface of a glass vessel, when it moves it leaves behind it a circular cloudy mark 
where the sucker had been adhering. When a number of them have been kept for a 
day or so in a small vessel, the bottom is found to be covered with a slimy layer, 
which may be removed as a thin pellicle. This proves on microscopic examination 
to be a colourless jelly, through which myriads of the rods are scattered—the whole 
very closely resembling a Zooglwa. 
The glands above described are undoubtedly the equivalents of the rhabdite- 
forming glands as they occur in the Rhabdoccele Turbellaria. The character of the 
cells, the nature of the bodies developed in them, the arrangement of the ducts in 
strands (“Stiibchenstrassen”) and their distribution about the anterior end of the 
animal all closely correspond. Whether in 7emnocephala the cells that form the 
rhabdites also produce the viscid matter in which they lie, or a special set of the cells 
have that function, as occurs, according to v. Graff, in the Rhabdoceeles, is uncertain: 
I incline to the former view, each rod, as it lies in the cell, being surrounded by a 
zone of uncolourable clear matter which is probably the viscid matter in question. 
As to the special function of the rhabdites, it is possible they have some influence on 
the consistency of the secretion—making it thicker or increasing its glutinous 
qualities. It is possible that they are themselves of a glutinous consistency, and aid 
in cohesion when in the act of protruding from the openings of the pore-canals. But 
this latter view seems no more probable than Schultze’s* theory that they have an 
influence on the tactile sensibility of the surface by offering resistance to pressure in 
the same fashion as nails and similar hard structures: it seems very unlikely that a 
function of this kind would be performed by bodies that are being cast off constantly 
by hundreds. Von Graff's observationt that the rhabdites are most abundant 
towards the anterior end, and much more numerous in sensitive and active forms, 
would seem to indicate that they have some function—unless we are to look upon 
them as an excretion—but does not seem to tell very specially in favour of 
Schultze’s theory. 
Much less numerous and less constantly in action are certain of the integumen- 
tary glands, the secretion of which passes to the ventral surface of the body around 
the genital aperture. Only exceptionally are the pore canals in this region found to 
be charged with the secretion, which contains solid elements shorter and thicker than 
those of the tentacular glands. The secretion is in this case most probably utilised 
to form the viscid material by means of which, in some of the species, the eggs, as 
will subsequently be explained, are united together when laid. 
* “ Beitrage zur Naturgeschichte der Turbellarien.” 
+ Tom. cit. p. 58. 
