284 H. M. WOODCOCK. 



There are, in addition, two or three forms, which are most probably to be 

 placed in this family, but which are not yet sufficiently characterised for 

 their generic position to be settled. It is, for instance, quite likely that 

 Leger's parasite Crithidia fasciculata (see above, p. 269) from females 

 of Anopheles maculipennis is sufficiently allied with Trypan o- 

 morpha for the two forms to be united in the same genus, in which case, 

 of course, the name Crithidia will take priority. 



Sub-order. — H eteromastigina. 



Family. — Trypaiiosomatidte, Dofl.^ emend. 



Flagellates^ in the great majority of instances liasmal para- 

 sites, derived from a billagellatej Bo do -like type, in which 

 the posteriorly-directed Hagellum (the so-called trailing 

 llagellum) is always present and attached to the body by 

 means of an undulating membrane, of which it constitutes the 

 thickened edge. The other, the anterior, flagellum may or 

 may not persist. Three genera so far distinguished. 



Genus Trypanoplasma, Lav. and Mesn., 1902. The 

 anterior tiagellum is present. Both flagella are inserted close 

 together at or near the anterior end of the body. Three species 

 certainly known, which can be arranged in two groups : 



(a). The anterior flagellum is well developed, and the free portion of 

 both flagella are of about equal length. 



T. borreli, L. and M., 1902. Length i from 20-22 ft, of free flagella 

 13-15/*; breadth 3^-4.| a* (figs. 17 F, G, 18). Hosts: (V.)- Leuciscus 

 (Scardinius) erythrophthalmus, rudd, and Phoxinus Isevis, 

 minnow ; (I.) not yet known. 



T. varium. Leg., 1904. Length (medium) about 25/*, of free flagella 

 18-20/*. Hosts: (V) Cobitis barbatula, loach; (I) Hemiclepsis 

 marginata, perhaps also Piscicola sp., leeches. This parasite differs 

 from T. borreli by the rather longer flagella, and by its not having the 

 pronounced cytoplasmic granules of the latter form. Leger considers 

 specific distinction^ is also shown by the fact that, in streams containing 

 both loach and minnows, only the former are infected with this parasite. 



(u). The anterior flagellum is much shorter than the free portion of the 

 posterior one, and apparently tending to disappear. 



T. cyprini, Plehn, 1903. Medium length about 20 /* (fig. 17 H). 

 Host: (V) Cyprinus carpio, carp. 



' Of the body alone, independent of the flagella. 



- (V.) signifies vertebrate hosts; (I.) invertebrate ones. 



3 See remarks on specific distinctions, pp. 288—9. 



