114 ILLINOIS BIOLOGICAL MONOGRAPHS [324 



Measurements of a few associations with all dimensions expressed 

 in microns are as follows : 



Total length association 590 570 540 490 440 



Primite : 



Length protomerite 60 70 60 60 40 



Length deutomerite 230 200 210 210 190 



Width protomerite 150 140 170 180 120 



Width deutomerite 130 140 150 150 100 



Total length sporont 290 270 270 270 230 



Ratio 



length protom. : total length 1:5 1:4 1:4.5 1:4.5 1:5.7 



width protom. : width deutomerite 1 :1.1 1 :1 1 :1.1 1 :1 1 :4.1 

 Satellite : 



Length protomerite 50 50 50 40 50 



Length deutomerite 250 250 220 180 170 



Width protomerite 110 130 140 120 90 



Width deutomerite 150 180 180 170 120 



Total length sporont 300 300 270 220 210 



Ratio 



length protom.: total length 1:6 1:6 1:5.4 1:5.5 1:4.2 



width protom. : width deutomerite 1 :1.3 1 :1.4 1 :1.3 1 :1.4 1 :1.3 



Diameter cysts 350 300 350 



GREGARINA STYGIA Watson 



[Figure 206] 



1915 Gregarina stygia Watson 1915:33 



This new species was taken from Ceuthophilus stygius (Scudder), 

 hosts found in an unused cistern on Dr. C. B. Davenport's grounds, at 

 Cold Spring Harbor, L. I. 



The infection was heavy, as many as five hundred parasites being 

 found in each of several hosts, and each of the twelve examined con- 

 tained at least a few parasites. The region of infection is the intestine. 



The sporonts are biassociative as adults. The longest association 

 measured SQOjj,. The sporonts are barrel shaped, the maximum length 

 recorded being 180/a and the maximum width 100/i,. The protomerite is 

 nearly hemispherical in the primite and is flattened in the satellite. The 

 deutomerite is widest at or in front of the middle portion. The satellite 

 is somewhat more slender than the primite and is of the same length or 

 a little shorter. The endocyte is dark tan in color, not very dense in 

 either deutomerite or protomerite, and the nucleus is easily visible in 



