LANKESTERIA. 79 



large nuclei and may be regarded as female gametes, while 

 those by the other have small nuclei and may be regarded as 

 male gametes. The zygotes become elongated and develop 

 into spindle-shaped sporocysts ; and in each sporocyst eight 

 sporozoites are developed. When the adult mosquito hatches 

 from the pupal case, its Malpighian tubes contain gametocysts 

 filled with sporocysts. The gametocysts then rupture, sporo- 

 cysts escape into the cavity of the Malpighian tubes, and 

 make their way to the intestine, whence they pass into water 

 to await ingestion by other larvse. 



Dimensions. — A free-hving trophozoite measures from 50- 

 200^ in length ; a mature sporocyst measures lOyu, by 6/x. 



Remarks. ~R^y (1933) has pubhshed his observations on 

 this form. Accorduig to him two types can be readily 

 distinguished. Those which mfest the oesophagus and anterior 

 part of the mid-gut, where the chitinous hning is thin and 

 smooth, are always of intracellular habit and possess very 

 feebly developed epimerites ; while those in the posterior 

 part of the mid-gut, where the epithehum is covered by a thick- 

 ridged chitin, bear a definite epimerite and are all growing 

 extracellularly, only anchored to the epithehum by the 

 epimerite embedded m. the host-cell. The epimerite is shaped 

 like an open umbrella connected by a very short handle. 

 The youngest forms in both cases measure 10/u. by 4-5^. 

 At the anterior end of the body there is a clear cone-like zone, 

 which takes up a dark, homogeneous stain, and which, according 

 to Ray, is comparable with the protomerite of septate Gre- 

 garuies. Such differentiation of the anterior portion of the 

 cytoplasm is, however, not unknown in other Monoeystids 

 possessmg an epunerite {vide Bhatia and Setna, 1927, figs. 18, 

 19, & 23), and xmless there is a definite septum the organism 

 cannot be placed among the Septata. 



The iatracellular forms, when they become too large to 

 remain within the host-cells, enter the gut-lumen, where they 

 measure 150-1 94 /z by 3 1-34 /x. The extracellular forms 

 attain the same size and, when mature, become detached, 

 leaving the epimerite embedded in the epithehum. 



Habitat. — Stomach of the larva, and Malpighian tubes of 

 pupa and adult mosquito, Aedes {8tegomyia) segypti (Linn.) : 

 India ; and Aedes [Stegomyia) albopictus Skuse : Bengal, 

 Calcutta. 



21. Lankesteria mackiei (Short & Swaminath). (Fig. 23.) 



Certain parasites, Mackie, 1915, p. 948. 



A Gregarine, Christophers, 1924, p. 6 ; Wenyon, 1926, p. 1151. 



Monocystis mackiei. Short & Swaminath, 1927, pp. 539-52, pis. li- 



Uv, figs. 1-18. 

 A Gregarine, Knowles, 1928, p. 501. 

 Lankesteria mackiei, Reichenow, 1929, p. 890. 



