THE HAEMOFLAGELLATES 



255 



create, namely, T. undulans and T. elegans, is somewhat doubtful. Button 

 and Todd have described two very long forms from Gambian frogs, which 

 they have named T. mega and T. karyozeukton ; these forms exhibit 

 peculiarities in the cytoplasm (see p. 212), and in the latter parasite a 

 chain of chromatic granules runs from one nucleus to the other (Fig. 8, D). 

 A type which is certainly distinct is T. inopinatum, Sergent, from the 

 edible frog. This parasite (Fig. 8, c) is slender (25-30 //, by 3 /*), and 

 resembles a Mammalian or Piscine form. Another well -characterised 

 species is T. nelspruitense, Lav., in which the body is very vermiform and 

 the free flagellum very long (Fig. 8, E). 



(e) Forms parasitic in fishes. Trypanosomes occur very frequently 

 in fishes, and a great many species have been described. T. remctki, 

 Lav. and Mesn. This para- 

 site occupies about the same 

 position among Piscine Try- 

 panosomes as does T. lewisi 

 among Mammalian ones. It 

 is a slender form, with taper- 

 ing, pointed extremities. The 

 trophonucleus is in the pos- 

 terior half of the body. Para- 

 sitic in Esox lucius, the pike. 

 Laveran and Mesnil have dis- 

 tinguished two varieties, based 

 upon the considerable differences in size met with, namely, var. parva, 

 medium length 30 ft, of free flagellum 10-12 //,, with breadth lJ-2 /A ; and 

 var. magna (Fig. 8, L), minimum length 45 //,, of which 17-20 //, is for the 

 flagellum, and breadth 2-2 /A. T. cobitis and T. carassii (Mitrophanow) 

 were among the first Piscine forms to be described, and probably corre- 

 spond to many of those seen by Danilewsky. T. granulosum of the eel 

 is a remarkably long, eel-like form (Fig. 8, K), 70-80 /A by 2-3 p. The 

 kinetonucleus is relatively very large, as is often the case in Piscine forms, 

 and close to the anterior end, which is sharply acute. Several forms 

 have been observed in flat-fish, certain of which (e.g. T. flesi, Lebailly) 

 belong to a different type, being relatively wide, with only a short 

 flagellum. From Elasmobranchs, two very large forms (T. scyllii and 

 T. raiae} have been described by Laveran and Mesnil ; these attain a 

 length of 70-80 /A, and usually have the body coiled up on itself (Fig. 

 38). 



Fm. 38. 



A, T. scyllii ; B, T. raiae. x 1200. 

 (After L. and M.) 



APPENDIX. 



(A) THE " LEISHMAN-DONOVAN- WRIGHT " BODIES. 



Although these remarkable bodies have not been shown yet to 

 possess an actual trypaniform structure, the fact that they are known 

 to give rise to Flagellate phases of very Herpetomonadine character 

 points so conclusively to their connection with that type of parasitic 

 Flagellate, and is of such importance as proving that a parasitic Flagellate 



