397] STUDIES ON GREGARINES— WATSON 187 



GREGARINA TENEBRIONELLA Watson 



[Figure 174] 



1915 Gregarina tenebrionella Watson 1915 :32 



Host: Larva of an unidentified member of the family Tenebrioni- 

 dae. Location: Urbana, Illinois, October, 1914. 



The intestine of the host was heavily infected, with a hundred or 

 more associations. 



The sporonts are biassociative and the shape is that characteristic of 

 this genius. The animals are very small and subglobular. The protome- 

 rite of the primite is as wide at the base as throughout the posterior third 

 of the body. Its anterior end is well rounded, without a papilla at the 

 apex. In the satellite, the width of the protomerite is about equal to the 

 height, although it is more or less flattened top and bottom. The length of 

 the protomerite of the primite is one fourth the total length. The deuto- 

 merite of the primite is short, broad, globose, widest through the median 

 portion and broadly rounded behind. In the satellite it tapers slightly 

 and is less globular in shape, being one third to four fifths as wide as the 

 deutomerite of the primite. The primite is larger in every instance re- 

 corded than the satellite, often longer by one third. 



The color of this species is pale gray. The protoplasm is not dense in 

 any part of the body and the protomerite is almost devoid of protoplasm. 

 The granules of the body are not homogeneous, smaller being interspersed 

 with larger. The satellite is more nearly transparent than the primite. 

 The nucleus is spherical, one fourth to one third the width of the deuto- 

 merite in its diameter ; it is not visible in vivo in the primite but generally 

 so in the satellite. The interlocking device between the sporonts is weakly 

 developed and the individuals often barely touching are easily displaced. 

 Trophozoites and cysts were not seen. Movement consists of a slow uni- 

 form progression ; contortion was not noted. 



A table of measurements follows, in which dimensions are given in 

 microns : 



Total length association 140 137 129 109 



Primite : 



Length protomerite 17 18 15 16 



Length deutomerite _ 53 53 46 46 



Width protomerite _ 23 20 25 20 



Width deutomerite 42 37 38 35 



Total length sporont _ 70 70 61 62 



Ratio 



length protom. : total length 1 :4.1 1 :3.9 1 :4 1 :3.9 



width protom, : width deutomerite 1 :1.8 1 :1.8 1 :1.5 1 :1.7 



