cells of doubtful origin, containing a large number of 

 yellowish or black granules of large size. 



A peculiar phenomenon takes place in the wall 

 of the sac as digestion proceeds ; the inner layer 

 escapes through the meshes of the outer in the form 

 of a number of herniae, so that the whole gut appears 

 as if studded with cysts ; a condition very marked in 

 Ornithodorus, but not to the same extent in Eurhipi- 

 cephalus. 



Salivary Glands. By displacing to one side the 

 whole of the diverticula, make out the large salivary 

 gland of each side lying over the bases of the first and 

 second legs (Fig. 101). 



Lifting up the salivary gland by its posterior end, 

 trace forward the salivary duct till it enters the 

 chitinous ring of the pharynx. 



Examine in the fresh condition and ascertain 

 that 



(1) The glands are composed of immense num- 

 bers of globular acini opening into short lateral ducts, 

 which in turn open into a central large duct (Fig. 102). 



(2) Each acinus consists of several large cells, 

 which exhibit different appearances at different stages 

 and under different conditions of preparation. Note 

 the globules of secretion packing these cells when 

 mature. 



(3) In sections note a large clear cell at the point 

 of entrance of the duct, and the different stages in the 

 formation of the large secretory granules. 



Coxal Glands. Lying partly under the salivary 

 gland and partly internal to this structure observe a 

 large flask-shaped organ, the coxal gland, conspicuous 

 from the number.pf tracheae which supply it (Fig. 101). 



Cephalic Glands. By displacing the diverticula 

 from the extreme anterior portion of the body make 



