204 WAGENER, ON GYRODACTYLUS ELEGANS. 



be traced tlirougli the structureless integument. At the 

 apex of the cephalic lobe^ a glutinous, viscous matter may 

 often be seen escaping, which in appearance may be closely 

 compared to the filaments by which the structureless 

 integument is traversed. Immediately behind the inferior 

 larger granular body, beneath the dorsal surface of the 

 animal, are situated twelve to fifteen cells in close apposition, 

 like those of tesselated epithelium, on both sides of the animal, 

 and covering the outer side of the intestine. The uppermost 

 of these cells are the largest, and they gradually become less 

 and less downwards, so that it was impossible to determine 

 the inferior boundary of the cellular layer. The nucleus and 

 nucleolus of the cells resembled those of the glandular cells 

 above described. The contents were quite colourless and 

 finely granular, but very transparent. 



Besides these unicellular glands, as they may be termed, 

 three other similar, very minute aggregations of cells are 

 placed on each side of the oral cavity, from which three 

 brown, fine granular streaks proceed transversely to the mesial 

 line of the animal, above or on the dorsal aspect of the oral 

 cavity, terminating with a slight curve outwards. 



On the back, rather higher than the mouth, I noticed four 

 large, clear, fine, granular, cellseform bodies, close together, 

 but whose nature remains quite obscure. 



All these cellseform bodies, or unicellular glands, would 

 seem to be comparable with those which are met with in the 

 cephalic lobes of the species of Dactylo gyrus. The four 

 cellseform bodies last mentioned probably correspond with 

 those lying above the mouth in Dactylogyrus, and which 

 from their brown hue present a very peculiar aspect. 



With them also may be associated the bodies existing in the 

 integument of many Trematodes and Cestodes, first described 

 by me under the name of " villi," or '' villiform bodies." 

 These also are furnished with a process filled wdth a brown 

 granular material, arising from a sacculus in which a clear 

 nucleus and opaque nucleolus may very frequently be seen, 

 and terminating in the integument. 



In the Cestodes it may be readily observed that an oil-drop 

 is gradually formed at the spot corresponding to the termina- 

 tion of the cell-process in the integument, and that this drop 

 of oil, gradually enlarging, is at last detached, a new drop 

 appearing in the same place. The contents of the sac, in 

 consequence of this, are rendered clearer, the number of fine 

 granules is lessened, the nucleus appears to float loosely in 

 the clear fluid, containing minute particles of the granular 

 material ; whilst a delicate, double contour line indicates the 

 wall of the sac. 



