281] STUDIES ON GREG ARINES— WATSON 71 



cyte. The latter is here very thin and readily breaks, with a consequent 

 extrusion of the endocyte. The nucleus is spherical, generally visible in 

 the adults and contains one large karyosome which is visible without 

 staining. 



The trophozoite of Stenophora impressa was studied in sections 

 made of the intestine of the parasitised Parajuli. The young parasites 

 lie imbedded between the cells of the intestinal epithelium, having made 

 a place for themselves by the absorption and destruction of the cell 

 originally entered, and by the absorption, destruction, and pushing aside 

 of contiguous cells; they lie with the apex of the protomerite next the 

 mesothelial wall. As is often the case with the Stenophoridae, there is 

 never developed an epimerite. Since the whole parasite lies embedded, 

 there is abundant surface through which osmosis may take place without 

 the additional presence of an epimerite. The protomerite of trophozoites 

 is often deeply embedded in the deutomerite, like a cork in the neck of a 

 bottle. 



Two types of movement were observed. A rapid gliding over the 

 surface at the rate of 6fi per second was very common. This form of 

 movement persists for an hour or more after the animals are placed on 

 the slide. Partial rotation of the body on its own axis and a bending of 

 the body to an angle of about 45° were frequent. The epicyte in the re- 

 gion just below the septum is very flexible, resulting in a nodding of the 

 protomerite from side to side. The extension of the upper part of the 

 deutomerite which causes the protomerite to drop is effected slowly, but 

 withdrawal of protoplasm is done by a sudden jerking movement which 

 restores the normal shape. 



Cysts 160)Lt in diameter were found, but none could be induced to 

 develop to completion in a water medium. 



This species differs from Stenophora lactaria in a) general shape of 

 the deutomerite, b) shape of the posterior end of the body, and c) shape 

 of the nucleus. 



A table of the various dimensions given in microns follows : 



Total length of body.- 155 270 



Length of protomerite 20 30 



Length of deutomerite 135 240 



Width of protomerite 30 35 



Width of deutomerite 70 70 



Katio 



length protom. : total length 1 :7.5 1 :9 1 :10 1 :10 1 :11 1 :11 



width protom. : width deutom. 1 :2.3 1 :2 1 :2 1 :2.3 1 :2.4 1 :2.1 



