348 FAMILY: TRYPANOSOMID.^ 



SYSTEMATIC DESCRIPTION OF GENERA AND SPECIES. 



Genus: Leptomonas Kent, 1880. 



The genus Lejjtoinonas, as defined above, includes flagellates which in 

 their life-cycles exhibit both leishmania and leptomonas forms, and which 

 are confined to invertebrate hosts. 



Biitschli (1878) described a flagellate which he found in the gut of a 

 nematode {Trilobus gracilis), and Kent (1880) named it Leptomonas 

 butschlii as the type of the genus. Unfortunately, this flagellate has not 

 been studied in the light of present knowledge, so that it is still uncertain 

 if it conforms with the definition of the genus Leptomonas given above. 



A very large number of species have been discovered in invertebrate 

 hosts, mostly arthropods, and of these anything like a complete life-history 

 is known only in a few instances. The form seen by Biitschli in the 

 nematode T. gracilis has already been mentioned. Chatton (1924) 

 records one seen by him in a marine nematode. Amongst the Mollusca, 

 Porter (1914) described L. patellce from the limpet Patella vulgaris, and 

 Mello (1921) L. jmchylabrcE from another mollusc, Pachylabra moesta. 



Leptomonas ctenocephali (Fantham, 1912). — Though Patton (1908c) 

 had seen a leptomonas in the Indian flea, Ctenocephalus felis, and its larvae, 

 the flagellate of the dog flea, C. canis, was first seen by Basile (1910a), who 

 mistook it for developmental forms of Leishmania donovani. The same 

 error was made by Basile and Visentini (1911), Sangiorgi (1911), Mar- 

 zocchi (1911), and Alvarez and da Silva (1911). The rounded leishmania 

 stages of the parasite were seen by Swellengrebel and Strickland (1910). 

 Noller (1912c^, 1914) discovered the flagellate in dog fleas and their larvae 

 in Germany, and concluded that it was a specific parasite distinct from 

 L. donovani. He studied the infection in fleas, and noted that it was 

 usually confined to the hind-gut, which was often completely lined with 

 attached forms. Fantham (1912) proposed the name Herpetomonas 

 ctenocephali for the flagellate, and Brumpt (1913) the name H. pseudo- 

 leishmania. The writer (1913a) observed the flagellate in dog fleas in 

 England, and later (1914a) in Malta, while da Silva (1913) studied it in 

 connection with attempts to transmit kala-azar in Portugal. Laveran 

 and Franchini (1919), Chatton (1919), Tyzzer and Walker (1919), Shortt 

 (1923), and Drbohlav (1925) studied cultures of the flagellate, and noted 

 that they differed from those of L. donovani. 



Though the flagellate of the dog flea is named Leptomonas ctenocephali, 

 it must be recognized that morphologically indistinguishable forms have 

 been previously described and named from other fleas, and if these should 

 be proved to be identical with that in the dog flea, the name given to the 



