315] STUDIES ON GREGARINES WATSON 105 



The protomerite is 50//, long. Eatio length protomerite : total length : : 

 1:8; width protomerite : width deutomerite : : 1 : 1.3. Protomerite 

 subspherical, flattened at septum, width equal to length. Constriction 

 at septum. Deutomerite elongate cylindrical broadly rounded behind. 

 Nucleus spherical with several karyosomes. Young associations more 

 slender, protomerites greatly attenuated. Cysts spherical or ovoidal. 



Taken at Rio Janeiro, Brazil. Host: Periplaneta orientalis (L.). 

 Habitat: Intestine and coelom. 



de Magalhaes names the species serpentula from the manner of 

 movement. 



"- a m'ont paru rappeler la forme de la tete d'un serpent et ses mouvements." 



The author found instances in which more than two sporonts were 

 attached : 



"Celli-ci (espece) fournit frequement des examples d'association de plusieurs 

 invidis disposes en file; deux trois et plus sont accoles par leurs extremites op- 

 posees. D'autres fois, ils forment des groupes constitues d'un plus gros exemplaire, 

 a 1'extremite posterieure duquel sont accoles deux, trois, cinq satellites plus petits." 



These phenomena are observed in rare instances throughout the genus 

 Gregarina. 



This species is quite distinct in characteristics from G. blattarum 

 Sieb., from the same host and its authenticity is not questioned. 



GREGARINA RIGIDA (Hall) Ellis 

 [Figures 194, 197, 198, 271, 290-333, 336-338] 



1907 Hirmocystis rigida Hall 1907 :149-174 



1907 Gregarina melanopli Crawley 1907:223 



1913 Gregarina rigida Ellis 1913b:267 



1913 Gregarina melanopli Ellis 1913c:82-3 



1915 Gregarina rigida Watson 1915:34-35 



Gregarina: Sporonts biassociative, rather stout bodied. Maxi- 

 mum length of association 1425/*, average length 550/x. Sporonts 250 to 

 750^ long, 130 to 210^ wide. Ratio length protomerite : total length : : 

 1 : 3 to 1 : 6 (primite) ; length protomerite : total length (satel- 

 lite : : 1 : 5 to 1 : 16 ; width protomerite : width deutomerite : : 1 : 

 1.4. Protomerite somewhat flattened, width sometimes three times the 

 height, generally less. Constriction at septum more or less indistinct. 

 Deutomerite cylindrical or barrel shaped, little wider than protomerite, 

 ending in a broadly rounded or flattened square cornered extremity. 



