590 FAMILY: TRYPANOSOMIDiE 



of T. rotatorium, have been used for tryi)anosomes of frogs and toads, apart from 

 those already given: T. mega Button and Todd, 1903; T. Icaryozeukton Dutton and 

 Todd, 1903; T. rotatorium var. nana Ed. and Et. Sergent, 1905; T. nelspruitense 

 Laveran, 1905; T. belli Nabarro, 1907; T. borelli Marchoux and Salimbeni, 1907; 

 T. hijlce Franga, 1908; T. leptodactyli Cariui, 1907; T. innominatum Pittaluga, 1905; 

 T. somalienselixuiwyii, 1906; T. bocrt</ei Fran§a, 1911; T.hocageivaiY.imrvaSinA magna 

 MathisandLeger, 1911 ; T.c7*fl<^oBiMatliisandLeger, 1911 ; TJwmidrtAverinzev, 1918. 



Similarly, in the case of T. inojnnatum the following names appear to be 

 synonyms: T. undulans Franca and Athias, 1906; T. elegans Franga and Athias, 

 1906; T. hendersoni Patton, 1908. 



Laveran and Mesnil (1912) arrange the trypanosomes of frogs and toads in four 

 groups. They separate from the two species named above T. leptodactyli of Lepto- 

 dactylus ocellatus of Brazil and all the trypanosomes of toads. Fran9a (1925) 

 believes that T. mega and T. haryozeulcton of Bufo regularis are good species. 



Trypanosoma rotatorium (Mayer, 1843). — As a result of the work of 

 Noller (19136), it would appear that this trypanosome is primarily a 

 parasite of the tadpole, and is handed on from one tadpole to another by 

 the leech, Hemiclepsis marginata. In the tadpole, and also in young frogs, 

 the flagellate is of the usual narrow trypanosome type (Fig. 239, 1-2). In 

 older frogs there appear many remarkable forms which are to be regarded 

 as derived by overgrowth from the more typical trypanosomes of the 

 tadpole (Fig. 239, 11-12). 



Morphology. — The tadpole trypanosome, according to Noller (19136), 

 has a body measuring from 25 to 35 microns in length. The nucleus lies 

 at the centre of the body, and is 2 to 2-8 microns in diameter. It is 

 spherical, and in properly fixed specimens is seen to have a central karyo- 

 some. The flagellum is 12 to 15 microns in length. The posterior end 

 of the body is sharply pointed and the undulating membrane is well 

 developed. Trypanosomes first appear in the tadpole five or six days 

 after exposure to infection by the leech. The first trypanosomes to 

 appear are small and narrow, and it is about the tenth clay after exposure 

 that the infection reaches its height, and the more typical trypanosomes 

 corresponding with the measurements given above appear. They are, 

 however, not numerous, as only about twenty occur in a square (18 by 

 18 mm.) cover-glass preparation of the blood. Reproduction takes 

 place in the usual manner by longitudinal division. Noller was unable to 

 discover any intracellular forms or stages of multiple division as described 

 by Machado (1911), nor was he able to obtain any evidence justifying the 

 separation of any of these trypanosomes into male and female individuals, 

 as this observer has done. 



The trypanosomes of the adult frog occur in three main types: 



1. Long narrow forms with well-developed undulating membrane, 

 spherical nucleus, compact kinetoplast, sharp-pointed and drawn-out pos- 

 terior end, and flagellum. The periplast may be longitudinally marked. 



