THE GREGARINES AND COCCIDIA 339 



The Gregarinoidea are classified as follows : 



Suborder I. Eugregarince (without Schizogony). 



Tribe I : Acephalina. Without an epimerite and non-septate ; 

 typically, though by no means invariably, " ccelomic " parasites. 

 Example : Monocystis, with several species parasitic in the vesiculse 

 seminales of earthworms, and many allied genera and species ; 

 see especially Hesse. Also many other genera parasitic in various 

 hosts echinoderms, ascidians, arthropods, etc. 



Tribe 2 : Cephalina. With an epimerite in the early stages, at 

 least, of the trophic phase ; in one family, Doliocystidce, non-septate, 

 but all others septate, with protomerite and 

 deutomerite, or with many segments (Tcenio- 

 cystis, Metamera). Typically parasites of the 

 digestive tract, most common in insects. 



This tribe comprises a great number of 



families, genera, and species ; see Minchin FIG. 150. " Gymno- 



(589). The type-genus Gregarina (Clepsy- spore" of Porospora 



7 x . 1 gigantea, consisting of 



anna) comprises many common species, such a number of sporo 



as G. ovata of the earwig, G. blattarum of zoites arranged radi- 

 the cockroach, G. polymorpha of the meal- SJt; ThSh 

 worm (Fig. 7, p. 9), etc. Other well-known contains a chromatinic 

 species wePterocephalus (Nina) nobilis, from 

 the centipede (Scolopendra spp.) ; Stylo- 

 rhynchus longicollis (Fig. 142), from the cellar- beetle, Blaps mortisaga, 

 and many others. The family Doliocystidce contains species parasitic 

 in marine Annelids. 



Suborder II. Schizogregarince (with Schizogony). 



Various methods of classifying the Schizogregarines have been 

 proposed. Leger and Duboscq (645) divide them into Monospora, 

 which produce a single spore in the sporogonic cycle (example : 

 Opkryocystis) ; and Polyspora, which produce many spores. Fantham 

 proposes to divide them into Endoschiza, in which the schizogony 

 takes place in the intracellular phase, as in Selenidium and Ecto- 

 schiza, in which the schizont is a free trophozoite, as in Ophryo- 

 cystis and Schizocystis ; the aberrant genus Siedleckia is probably 

 to be referred here also (see Dogiel, 606). The present state of 

 knowledge is hardly ripe, however, for a comprehensive classifica- 

 tion of the schizogregarines, and it may well be doubted whether 

 they are to be considered as a homogeneous and natural suborder ; 

 some of the families of the Schizogregarinae appear to be more 

 closely allied to particular families of Eugregarinse than to one 

 another. Leger (617, ii.) points out that the family Schizocystidce 

 shows close affinities with the eugregarine family Actinocephalidce. 



