282 SPOROZOA. 



development. Leger and Bouilliez (1913) inoculated the 

 parasite into a number of monkeys, including Cercopithecus sp. 

 (the common host of P. kochi), with the result that many of 

 them died of heavy infections. Quinine, even in large doses, 

 appeared to have no influence. Donovan (1920) examined 

 a large number of specimens of Silenus sinicus and Pygerythrus 

 priamus {^=Preshytis j^riamus) in the Nilgiri Hills, South India, 

 but with negative results. Subsequently he found a Plasmo- 

 dium, in a blood-film from a specimen of S. sinicus from the 

 same region, which he considered as morphologically identical 

 with that found in 8. irus {=M. cynomolgus). He also 

 mentions having seen Plasmodium in several other apes 

 and monkeys, but does not give any description or cite 

 localities. 



Francliini (1927) found in Macacus cyoiomolgus a parasite 

 which showed many resemblances with P. malariss. Macfie 



(1928) found P. inui in a young baboon in Africa. Reichenow 



(1929) observed that P. inui does not show enlargement 

 of the corpuscles and Schiiffner's dots, whilst P. cynomolgi 

 shows these, but stilJ came to the conclusion that these forms 

 are probably identical. 



Sinton and Mulligan (1932), in a specimen of Silenus irus, 

 obtained an infection which later work showed was a mixed 

 one. They succeeded in isolating in S. rhesus, by blood 

 inoculation from the same naturally infected host, two mor- 

 phologically distinct types of Plasmodium, which they regard 

 as P. inui var. cynomolgi and P. knowlesi. They obtained 

 the sporogony cycle in a number of mosquitoes, and succeeded 

 in transmitting the infection to a healthy specimen of Silenus 

 rhesus by the bites of infected A. annularis Van der Wulp. 

 Napier and Campbell (1932) and KJnowles and Das- Gupta 

 (1932) also recorded a malarial infection in 8. irus, said to 

 have been imported from Singapore. Sinton and MulHgan 

 (1932 a) gave a critical review of the literature relating to 

 malarial parasites in lower monkeys, and came to the con- 

 clusion that the majority of species of Plasmodium described 

 from the lower monkeys fall into two main divisions, those 

 found in the African monkeys {P. kochi group) and those found 

 in the Oriental ones (P. inui group). According to them the 

 latter include P. inui Halb. & Prowazek {sensu restr.), P. inui 

 var. cynomolgi Mayer, P. inui var. gonderi, and P. knowlesi, 

 and the various previous records were arranged according 

 to this scheme. Later on, Sinton (1934 a, 1934 b) and Mulligan 

 (1935) have come to the definite conclusion that P. cynomolgi 

 is a distinct species and not a variety of P. inui, as the duration 

 of schizogony in the former is forty-eight hours and in the 

 latter seventy- two hours. 



