LA VERA NI A MALARIA 517 



Genus Laverania Grassi and Feletti, 1890. 



Definition. — Plasmodidse, in which the gametocyte is dissimilar 

 from the schizont, appearing in the form of a crescent. Schizogony 

 in the red blood cells in internal organs. 



Laverania malarise Grassi and Feletti, 1890 (Plate I.). 



Synonyms.— HcBmamosba malaricB Laveran, 1890; H. pmcox 

 Grassi and Feletti, 1890; H. laverani Labbe, 1894; H.immaculata 

 Grassi and Feletti, 1891; Plasmodum malarice var. quotidiance 

 Celli and Sanfelice, 1890; P. fmcox Dofiein, 1901 ; P. immacidatum 

 Schaudinn, 1902 ; P. falciparum Blanchard, 1905 ; Hcemomonas pmcox 

 Ross, 1899; Hcemosporidium undecimance Lewkowicz, 1892; H. sede- 

 cimancB Lewkowicz, 1892; H. vigesimotertiance Lewkowicz, 1892; 

 Hcematozoon falciparum Welch, 1897. 



Fig. 174. — Male Crescent OF Layer- Fig. 175. — Female Crescent of 

 awia w<2^an(^ (Grassi AND Feletti, Laverania malarice. (X 1,000 



1890). (X 1,000 Diameters.) Diameters.) 



(By JyTorman, through the kindness of J. J. Bell.) 



The young trophozoite begins as a very small parasite, which 

 quickly^forms a ring, of which the size is only one-sixth to one- 

 seventh of the diameter^of the enclosing red cell. This quickly 

 grows into an oval form, which becomes pigmented, while the en- 

 closing erythrocyte in stained preparations may show the so-called 

 Maurer's dots, the significance of which is not understood. 



The fully-grown schizont (size 4-5 /.t) is but rarely seen in the 

 peripheral blood, and the segmentation into merozoites (size 07 /^) 

 nearly always takes place in the internal organs, when eight to ten 

 or fifteen are formed. When this is in progress there is a great 

 tendency for the red corpuscles to cling together and to the Wall 

 of the vessel, and hence to give rise to obstruction of the circula- 

 tion, which produces the perniciousness of the fevers due to this 

 parasite. 



