Phylum Fungilli [ 213 



(Argao, 1908), the alternate host is a fly. In the gut of the fly, the spermatocytes pro- 

 duce the elongate sperms as outgrowths. The zygotes make their way into the wall of 

 the gut of the fly, grow, and produce very numerous sporozoites. These migrate to the 

 salivary gland, from which they are injected into pigeons. 



Leucocytozoon attacks birds; its cells become fairly large in certain blood cells 

 which become colorless and spindle-shaped. 



Family 2. Plasmodida [Plasmodidae] Mesnil in Bull. Inst. Pasteur 1: 480 (1903). 

 The malaria organisms, differing from Haemoproteus in that they multiply in the 

 erythrocytes of their hosts. With a few obscure exceptions, the species are construed 

 as a single genus Plasmodium. Three species attack man; they have perhaps done 

 mankind more injury than any comparable group of living creatures. Several com- 

 paratively poorly known species attack apes and monkeys. The alternate hosts of all 

 species are mosquitoes of the genus Anopheles. 



The vegetative individuals complete their growth within erythrocytes of their hosts 

 in more or less definite periods of time, and undergo multiple division; the erythro- 

 cytes then break up and release the merozoites. The chill and fever of malaria are as- 

 sociated with the destruction of erythrocytes. In the ordinary form of malaria, called 

 tertian malaria, development requires forty-eight hours, and the chill and fever occur 

 every other day. Another form, called malignant tertian or tropical malaria, exhibits 

 the same rhythm; it is distinguished by details of the appearance of the infected 

 erythrocytes. In the third form of malaria in man, called quartan, development re- 

 quires 72 hours, and the chill and fever occur every third day. 



The course of development in the mosquito is quite like that of Haemoproteus 

 Columbae in the fly. Some of the parasites inside the erythrocytes are gametocytes; 

 each female gametocyte in an erythrocyte swallowed by a mosquito develops into a 

 single egg, while each male gametocyte buds off several spirochaet-like sperms. The 

 fertilized eggs are able to move. They break into the epithelium of the gut of the 

 mosquito, grow into large globes, and become multinucleate; their protoplasts divide 

 into numerous masses of protoplasm each of which buds off large numbers of sporozo- 

 ites. The sporozoites are released into the body cavity of the mosquito, migrate to 

 the salivary gland, and are injected into whatever animal the mosquito may bite. 



The scientific names usually applied to the three species which cause human 

 malaria are not valid by priority. Extensive synonymy is given by Sabrosky and 

 Usinger, in their application to the International Commission on Zoological Nomen- 

 clature for action arbitrarily maintaining the current names (1944), and in the 

 report by Hemming (1950) of the action of the Commission. 



Certain structures in the erythrocytes of malaria patients were first recognized as 

 parasites by Laveran, 1880, who, in 1881, named them Oscillaria malariae. The 

 organism is believed to have been that of malignant tertian or tropical malaria. The 

 word Plasmodium, properly designating a certain type of body, was applied by Mar- 

 chiafava and Celli 1885, in the combination Plasmodium malariae, believed also 

 originally to have designated the agent of malignant tertian malaria. Feletti and 

 Grassi, 1889, introduced the generic name Haemamoeba, with two species, H. vi- 

 vax, the agent of tertian malaria, and H. malariae, that of quartan malaria; it is be- 

 lieved that the latter epithet was applied under the misapprehension that this was the 

 organism which Marchiafava and Celli had named. It appears that Liihe, 1900, is 

 responsible for the currently used names: 



Plasmodium vivax, the organism of tertian malaria; 



P. malariae, that of quartan malaria; 



