285] STUDIES ON GREG ARINES— WATSON 75 



body, and there is no indentation at its anterior end as in many of the 

 Stenophoridae. The anterior half of the protomerite is rather broadly 

 conical and is blunt at the apex. There is but a slight constriction at 

 the septum in extended individuals. The anterior end of the deutome- 

 rite is but little wider than the protomerite just in front of the septum. 

 The deutomerite gradualy widens, becoming twice the maximum width 

 of the protomerite. It is incompletely separated into two nearly equal 

 parts by a deep constriction at about the middle and behind this con- 

 striction the body is cylindrical, of practically the same width through- 

 out, terminating in a blunt, well rounded cone. 



The protomerite is transparent or nearly so, containing a few large 

 irregular deeply staining granules clustered near the septum. The deu- 

 tomerite is plain tan in color and contains smaller homogeneous gran- 

 ules densest just anterior to the constriction in the walls, least dense at 

 the posterior end, and otherwise fairly evenly distributed. The endo- 

 plasm is much less opaque than in many gregarines. The epicyte is 

 thick, transparent and of even width throughout except at the constric- 

 tion in the middle of the deutomerite where it becomes considerably 

 thicker. Longitudinal striations are easily discernible in the epicyte. 

 The myonemes are well developed, especially at the constriction and in 

 the region of the septum, and are indicated by a series of delicate some- 

 what reticular fibrillae embedded in the peripheral layer of the endo- 

 cyte and running crosswise of the body. The nucleus is visible in vivo ; 

 it is spherical and in diameter two thirds the Mdth of the body just 

 back of the deutomerite constriction. It lies just posterior to this con- 

 striction. One large karyosome is visible within. 



The epimerite evidently persists after its usefulness is over, and 

 was seen in one instance on a fairly large specimen free in the lumen of 

 the intestine. It is a large hyaline smooth knob with a short stalk broad 

 at the base. 



Neither sporozite nor cyst was seen. 



The parasite is fairly active. Gliding motion, accompanied by no 

 bodily contortion was observed at rates of 11 and 7/* per second. Each 

 rate was fairly constant for the given gregarine for a period extending 

 over several minutes. A contortion of the body is common, either with 

 no displacement of the body as a whole or in connection with the glid- 

 ing motion. In fact, it was difficult to find an animal in simple progres- 

 sion which was not at the same time performing some sort of contor- 

 tion. The region of the septum is very motile. Here the epicyte ex- 

 pands and contracts, with an inflow or withdrawal of the endocyte, just 

 as in the case of an amoeba. Tiny processes can be seen extruded sev- 

 eral at a time or a large portion of the endoplasm of the region may be 

 pushed out one at a time. In the latter case, the heavy and rigid proto- 



