THE HAEMO FLAGELLATES 



241 



even oblong bodies, attached, often in great numbers, to the 

 epithelial cells. The flagellum is either absent or reduced to a 

 short rostrum, serving for attachment (Fig. 29, D and G). The 

 t\vo nuclei (tropho- and kinetonueleus) lie close together, usually 

 near the base of the cell. In this phase, the general resemblance 

 to the Leishman-Donovan bodies may be quite marked. The 

 distinction between the two generic types is based upon the form 

 and size of the monadine phase. In Herpetomonas the body is very 

 elongated . and slender, often acicular, the posterior end usually 



FIG. 29. 



A, C, Herpetomonas (Crithidia) minuta ; D, attached (gregariniform) phases of same; B, H. 

 gracilis, Leger ; E. F, //. subulata, Leger ; G, attached phases of same. (After Leger.) x 1800. 



tapering away finely (Fig. 29, B and E). In Crilhidia, on the other 

 hand, it is much shorter and wider, of a pyriform shape ; the hinder 

 end is never drawn out, but terminates bluntly in a rounded or an 

 obtuse manner. The parasite Herpetomonas (Crithidia) minuta, L6ger, 

 appears to be intermediate, however, between these two types, some 

 individuals approximating to a Herpetomonad form (A), others to a 

 Crithidial one (Fig. 29, c). As a matter of fact, the classificatory 

 distinctions between these various Insectan Flagellates cannot be 

 regarded as at all settled. 



In many forms of Herpetomonas (e.g. H. muscae-domesticae, 1 H. 

 jaculum, or H. gracilis (B)), the kinetonucleus is situated near the 



1 //. muscae-domesticae is included here as a typical uiiiflagellate Herpetomonad. 

 Prowazek (69) described this form as possessing a pair of flagella, parallel to and 

 connected with one another ; he considered this parasite to be a bipolar type (on the 

 lines of Schaudhm's " Urhaemoflagellate") in which the body has been bent up so 

 that the two ends have come together and united, the flagella alone remaining 

 distinct. Leger observed no signs of two flagella in non-dividing individuals, either 

 of this species or others ; and the same is true of the describers of the numerous 

 other Herpetomonads. 



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