456 W, s. NICKERSON, 



when certain of these found their way to tlie exterior they were har- 

 dened and their form preserved as soon as they came into contact 

 with the fixing fluid. 



Another fact which seems to indicate that this layer lias arisen 

 as an exudation from the outer portions of the body, is found in the 

 character of the deeper surface of the material composing it. Where 

 the cuticula has been raised up slightly from the musculature beneath, 

 its lower surface shows a very irregular outline with projecting pro- 

 cesses corresponding to the interstices between the muscle fibres 

 beneath. It gives just the appearance to be expected if the material 

 forming the layer has made its way out or been slowly squeezed out 

 through the meshes of the muscle layer. It is hardly the appearance 

 to be expected of metamorphosed epithelium, and if the material were 

 derived from special glandular cells lying scattered beneath the muscu- 

 lature, we should not expect to find the processes of the material 

 reaching into all the spaces between the fibres, but only into those 

 which immediately overhe the special gland cells. 



The outer surface of the cuticula as seen in tangential sections 

 with a magnification of four or five hundred diameters presents an 

 appearance which also harmonizes well with this theory (»f the form- 

 ation of the cuticula. The whole surface is covered with minute 

 elevations, which give it a striking resemblance to the surface of grain 

 leather. 



If the increase in thickness of the layer is produced at the outer 

 surface by additions of material which makes its way through to the 

 exterior in small globules, it might naturally be expected to produce 

 just such a surface as I have described. 



Brandes ('92, p. 566) says, "Was nun das Vorkommen der Sub- 

 cuticulardrüsen anbetrifft, so glaube ich schon jetzt mit Sicherheit 



behaupten zu können, dass sie nirgends fehlen werden Sollten 



diese Drüsen aber wirklich trotz eingehender Untersuchungen irgendwo 

 nicht aufzufinden sein, so bin ich überzeugt, dass auch die Cuticula 

 des betreöenden Trematoden eine ausserordentlich geringe Ausbildung 

 zeigen wird." 



As 1 have already stated, it is not possible to distinguish any 

 différence in the character of the different cells making up the sub- 

 muscular layer of the i)ody of Stichocotyle, even with the aid of the 

 stains best adapted to differentiating glandular cells. It is equally 

 true that in this worm the cuticula does not .show "eine ausser- 

 ordentlich geringe Ausbildung"; on the other hand it has, as I have; 



