32SJ STUDIES ON GREGARINES— WATSON 115 



vivo. The sarcocyte is thicker at the septum and anterior ends of the 

 protomerite than elsewhere, but is fairly thick throughout. The, nu- 

 cleus is small and spherical and contains one or more large karyosomes. 

 Sections show that the cephalont possesses a single knobbed epi- 

 merite, slightly stalked. The sporozoite is spindle-shaped and contains 

 a large nucleus. Several sporozoites were seen in the sectioned intes- 

 tine lying free in the lumen or contiguous to the epithelial wall. 



Movement is sluggish and of the ordinary two types, gliding and 

 contortion. 



Cysts average 150/a in diameter. Dehiscence was not seen. 

 This species is not identical with Gregarina longiducta Ellis 

 (1913a :78-82), from Ceuthophilus latens and C. maculatus. Associations 

 of the latter average 800 - 900/* in length, the smallest observed being 

 465/A long. Large associations of G. stygia are only 350/* in length. Pro- 

 portions vary as well as lengths. 



The species differs from G. consohrina Ellis (1913:267) in size. 

 Sporonts of the latter species attain a length of 600/x,, those of G. stygia 

 not becoming longer than 180/x. 

 Satellite : 



No other species is recorded from the genus Ceuthophilus. 

 A table of measurements is appended herewith, all dimensions be- 

 ing given in microns: 



Total length associations 360 330 300 



Primite : 



Length protomerite 30 20 30 



Length deutomerite 150 140 120 



Width protomerite „ „ 60 40 55 



Width deutomerite _ „. 100 100 80 



Total length sporont 180 160 150 



Ratio 



length protom. : total length „ 1 :6 1 :8 1 :5 



width protom. : width deutomerite 1 :1.6 1 :2.5 1 :1.5 



Satellite : 



Length protomerite 20 25 30 



Length deutomerite 160 145 120 



Width protomerite 60 50 70 



Width deutomerite 80 60 80 



Total length sporont 180 170 150 



Ratio 



length protom. : total length.. 1 :9 1 :7 1 :5 



width protom. : width deutomerite 1 :1.3 1 :1.2 1 :1.1 



