gans vfhile the tick is yet feeding. Rectal discharge is very- 

 slight. These two methods of excretion are discussed in separate 

 sections below. 



Digestion in 0. inoubata apparently is much like that in 0, 

 3avignyi ,as descri'Eed by Christophers, abstracted below. "" 



Twenty-four hovirs after a meal the greatly distended di— 

 verticula contain a soft coagiilum from which a considerable anwunt 

 of fluid blood may drain. Blood corpuscles are apparently un- 

 changed. Scattered through the fluid are numbers of intensely 

 black, globular graniiles measuring from 5u to .5u or less in 

 diameter. In sections these granules are collected especially 

 at the periphery of the (fresh) blood, but they are also present 

 in large numbers scattered throughout the mass. The black gran- 

 ules are derived from a previous meal, and there is therefore a 

 considerable degree of mixture between the new blood and the 

 contents of the diverticula prior to the meal. 



Diverticula examined at some considerable time sifter diges- 

 tion show a number of reddish granules lying in the still partiaJ- 

 ly fluid blood. These are free from attachments and when washed 

 out faJ-l to the bottom of the dish or among the viscera. Each 

 is an entire cell containing a well-marked nucleus. Films of 

 the sac contents made twenty-fovir hovirs after a blood meal show 

 cells derived from the epithelium of the sac in addition to the 

 host's leucocytes. Many of these are evidently the smaller lin- 

 distended cells, previously noted as lying near the basement mem- 

 brane, now detached in preparation of the specimen. They contain 

 a large circxilar or oval nucleus and finely reticular or partial- 

 ly vacuolated protoplasm. Similar cells, but larger and with 

 portions of the vacuolated protoplasm stored with black granules, 

 are also seen. In addition to these cells of the sac epithelium, 

 there are other large, dark staining, circular cells with rather 

 small nucleus. Their substance is markedly vaciiolated and crowded 

 with matter that they evidently have engulfed, blood corpuscles, 

 black granules, chromatin fragments, etc. In section specimens 

 made even six hours after the ingestion of blood, they appear lying 

 apparently in isolated positions far removed from the sac v;alls. 

 These probably function as waxidering digestive cells. Their rela- 

 tion to the epithelium of the sac is not clear. As digestion ad- 



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