252 H. M. WOODCOCK. 



and mobile, and with nucleus and eentrosome (i. e. tvoplio- and kineto- 

 nucleus) distinct — stages intermediate, that is, between a Hismogregavine 

 and a Trypanosome.' (c) Progs quite free from all Hsematozoa and then 

 infected by placing HelobdellfB, whose digestive tube contained T. 

 inopinatum, upon them were found afterwards to contain only Lankes- 

 terella. 



Billet considers the Trypanosome phase to be very uncommon in the 

 frog, but of general occurrence in the leech, and, conversely, the Ha?mo- 

 gregarine phase to be absent, as such, in the Invertebrate host, but common 

 in the Vertebrate. T. inopinatum does of course occur in the frog — 

 Sergent (101) first described it in that host — but apparently it is only at rare 

 intervals that the parasites lose the Hjemogregarine condition and become 

 trypaniform. It may be pointed out in this connection that Sergent (103) 

 who has corroborated Schaudinn's researches, says that Trypanomorpha 

 in the Trypanosome-f oi'm is comparatively rare in the blood of the owl, but 

 common as Halteridium, and, vice versa, in the gnat the latter phase 

 is not represented. 



Further, Billet in a previous communication (4) has described forms 

 which he regards as intermediate between merozoites of a Lankesterella 

 and the typical trypaniform phases of T. inopinatum. He also observed 

 the latter penetrate into the red blood-corpuscles, losing the flagellum in so 

 doing, and then multiply in this endo-globular situation, either by binary 

 longitudinal fission or by schizogony. 



The study of this impoi'tant question of the life-history of 

 a Heematozoan, with regard to its bearing upon the relation- 

 ship between Trypanosouies and Hasmosporidia^ may also be 

 approached from exactly the opposite direction. In other 

 words, it is sometimes quite as easy, or even easier, to work 

 from the latter to the former, to look for a trypaniform phase 

 in a recognised and well-known Hfemosporidian. Some 

 very interesting instances of such a discovery are now to hand, 

 foremost ainoug them being one for which we are again 

 indebted to that marvellous investigator, Schaudinu. 



Tliis author states that he has observed the development of 

 a motile trypaniform phase at two points in the life-cycle of 



* Brumpt (10), it is important to note, has also observed in the ookinetes 

 of Hajmogregarina bagensis (from Emys leprosa) which he found in 

 the oesophageal and stomach diverticula of Placobdella catenigera, two 

 nuclear bodies, a large nucleus of the ordinary' type, and a smaller, highly- 

 staining body much resembling the eentrosome (i e. the kinetonucleus) of a 

 Trypanosome. 



