1'.>U7.] XATURAL SCIENX'ES OF PIIILAUKLPHIA. 223 



Dehiscence is by a single sporoduct, which may reach a length of 

 750 microns. A discharged cyst is shown in fig. 12. The residuum 

 is a loose mass of granules and debris which nearly fills the cavity 

 within. The duct is limited externally by a cuticular wall. Within 

 it is filled by a soft substance, through the center of wliich can be 

 seen the lumen along which the spores had passed. This lumen, 

 however, shows no definitive membrane, being merely a channel 

 through this soft substance, which is probably of the same nature as 

 the residuum. 



In one case observed, the spores still la}' in situ as they had been 

 projected from the duct. The duct was 600 microns long; the file of 

 spores 2,400. Hence the leading spore had reached a distance of 3 

 millimeters from the cyst. In consideration, however, of the size and 

 activity of the host, it is not easy to see how the scattering of the 

 spores over such an infinitesimal area can cut much of a figure in 

 their dissemination. 



Spores. — Rounded cylinders or barrel-shaped. Dimensions, 5 by 

 2.75 microns. 



Host. — Gryllus ahbreviatus Serv. The gregarines occurred in perhaps 

 25 per cent, of the crickets opened. But when present, they are 

 present in countless numbers, compact masses of gregarines as large 

 as peas being found. It does not seem likely that such extensive 

 infections can be due merely to the chance picking up of stray spores. 

 More probably we have here to do either with cannibalism or the 

 devouring of dead comrades. 



Gregarina melanopli sp. n. (PI. XVin, figs. C-9.) 



Protomeritc. — In the young solitary animals, the protomerite is 

 cubical, with rounded corners, to mammaliform, and often shows in 

 front a low, broad projection. In the associated gregarines, it has 

 the form of a greatly compressed hemisphere. 



Deutomerite. — In the young, cylindrical to flask-shaped. There is 

 generally a slight constriction in the middle. In the pairs, cylindrical, 

 but with a very variable ratio of length to breadth. Two cases are 

 shown in figs. 8 and 9, which are camera outlines of li\'ing gregarines. 



Epicyte. — Longitudinally striated. The following measurements of 

 its thickness are taken from a large pair: 



Primite. — 



Anterior tip of protomerite 5 microns. 



Sides of protomerite 5 " 



Sides of deutomerite 1-2 ^ " 



