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THE AMEBIC AX NATURALIST [Vol. XLIII 



that their life history manifests two cycles; the schizogonic or 

 vegetative cycle, in the blood of vertebrates and characterized 

 by asexual multiplication with the sporogonic, characterized by 

 sexual reproduction. They enumerate merozoites, schizonts, 

 sporonts, etc. Patton 3 recounting his work on the same objects 

 states that careful feeding operations with larval nymphal and 

 adult ticks under most favorable conditions at the King Insti- 

 tute, Madras, and several years' study of similar parasites in 

 amphibia and their transmitting leeches, for comparative pur- 

 poses, have entirely failed to elucidate the extra-corporeal life 

 histories of the intracellular parasites of either reptiles or 

 mammals. He regards the transmission of these parasites as 

 mechanical and questions the interpretation of the different 

 forms described by the other authors from the peripheral blood 

 of snakes. He inclines to consider all their forms as belonging 

 to a single species of haemogregarine and in closing calls atten- 

 tion to Prowazek's error in regarding cysts found in a pentastome 

 from a python as developmental stages of Hamogregarina 

 py thorns when in reality they represent part of a cycle of a 

 parasite peculiar to the pentastome and have nothing to do with 

 the haemogregarine of the snake. Patton might have cited 

 numerous similar cases of confusion between normal parasites 

 of a supposed transmitting agent and the missing developmental 

 stages of the parasite under investigation. 



In the same journal 4 Patton gives a brief though valuable 

 resume of the genus Herpetomonas which emphasizes certain 

 points of great importance in this connection. These flagellates 

 are parasitic in the alimentary tract of insects, though those 

 which occur in blood-sucking insects are in no wise related to' 

 blood parasites. Their developmental cycle consists of a pre- 

 flagellate, a flagellate and a postflagellate stage. The preflagel- 

 late stage presents round or oval bodies with nucleus and 

 blepharoplast, multiplies by simple longifission or multiple seg- 

 mentation, and occurs in the insect's mid gut. In the flagellate 

 stage the organism forms a single flagellum and is found in 

 both mid gut and hind gut, while the postflagellate stage is char- 

 acterized by massing of the herpetomonads in the midgut and 

 the formation of cysts which pass out in the feces. Many are 

 undistmguishable in their preflagellate stages and a partial study 



'^Parasitology, December, 1908. 



* Parasitology, December, 1908. 



