80 BRITISH TYROGLYPHIDjE. 



are distinctly nucleolated. At the point from which 

 the cells radiate is a minute chamber, which is really 

 the commencement of the duct, which is extremely 

 fine. This gland has considerable similarity to the 

 " reniform " salivary gland in Thy as and Bdella, and is 

 probably the homologue of that organ ; the cells are 

 usually filled with a fine and slightly granular secretion, 

 which stains very slightly with hosinatoxylin or carmine. 

 Gudden evidently saw this gland in Tyroglyphus xiro, 

 and figures it fairly correctly (PL A, fig. 7) ; he does 

 not say much about it, and it rather seems as if he 

 took the large individual cells for lobes, but it is an 

 extraordinary thing that he should have seen it at all 

 by the process he adopted ; that process would pro- 

 bably make the cells look lobe-like from endosmosis. 



The other gland consists of two or three similar 

 large cells, and is probably the homologue of the 

 anterior salivary gland in Bddla. 



The duct from these glands is extremely fine and 

 difficult to follow to its point of discharge ; but I am 

 almost certain that its course is practically similar to 

 that of the " main common duct " in Tliyas and ]>il<'ll<i-, 

 viz. the ducts from the two glands from the same side 

 of the body join not very far from the glands ; the 

 joint duct then runs along the side of the body, near 

 the cuticle, until it reaches a point almost opposite the 

 proximal end of the mandibles ; it then turns inward 

 and joins its fellow from the opposite side of the body 

 upon the roof of the rostrum between the mandibles ; 

 the two having joined form a short common duct, 

 which passes a short distance along the underside of 

 the roof of the rostrum, and discharges into the rear 

 of the mouth. 



Haller * appears to recognise the existence of two 

 salivary glands on each side of the body in the larva of 

 GlycyphuguB (Dermacarus) sciurinus ; he apparently 

 saw them, by transparency, through the skin. 



* " Ziir Kenntniss dev Tyroglypben und Verwandten," loc. cit., 

 p. 277, Taf. ix, fig. 14. 



