307 



diverticula which arise from the median sac. Ascer- 

 tain that the posterior and some of the lateral diver- 

 ticula are of extreme length, and pass round to^the 

 ventral surface, reaching to the neighbourhood of the 

 anus, vulva, and even the rostrum (Fig. 101). 



Some of the lining cells of the diverticula are 

 especially large, and project freely into the lumen. 

 These and other smaller cells become, during digestion, 

 loaded with jet black granules. 



'0ml fko dio 



}>/. 



Fig. 101. Alimentary canal and appendages of Ornithodoros 



and Eurhipicephalus (semi-diagrammatic} 



C.G = coxal gland ; Ce.G = cephalic gland ; D = ventriculum ; 



A.D = anterior diverticulum ; L.D lateral diverticulum ; 



P.D posterior diverticulum ; M.P.D. = median posterior 



diverticulum ; E.P.D. = external posterior diverticulum ; 



P = proventriculus ; R = rectum ; S salivary 



M.T. = malpighian tubule 



Some time after feeding, in the still partially fluid 

 blood, a number of reddish granules are seen with the 

 naked eye : they are really cells, wandering digestive 



