112 SPOROZOA. 



which may be binary or multiple fission or budding. As in 

 Ettgregabinakia, two full-grown trophozoites (sporonts) 

 associate and give rise to gametes, which conjugate to produce 

 zygotes. Each zygote becomes an oocyst. The number of 

 oocysts produced by each pair of gametes varies from one to 

 thirty. Each oocyst, popularly called a spore, contains one 

 to eight sporozoites. 



L6ger and Duboscq (1908) divided the suborder into Poly- 

 sporidea and Monosporidea according to the number of 

 oocysts produced by a pair of associated Gregarines. Fantham 

 (1908) on the other hand divided the group into Endoschiza 

 and Ectoschiza, according as schizogony took place within a 

 cell or was extracellular respectively. Keilin (1923) is of the 

 opinion that neither of these classifications is a natural one, 

 and that it is not impossible that the process of schizogony 

 has been secondarily acquired by some members of the 

 EuGREGARiNARiA and that the various genera of Schizogre- 

 GARINARIA wiU ultimately be distributed among the famihes 

 of the EuGREGARiNARiA. Wenyon (1926) and Ray (1930) 

 have supported this view. 



Reichenow (1929) does not group the genera into families, 

 but Minchin (1912), Doflein (1916), and Calkins (1926) recog- 

 nized a number of families, each based on one or two genera. 



Identification Table of Families. 



1 (7). Gametocyst contains a single oocyst . 2. 



2 (4). Oocyst contains a single sporozoite . . 3. 



3. Gregarine spirally wound or cres- [Dub. 



centic ; schizogony intracellular . . . Spirocystidse * Leg. & 



4 (2). Oocyst contains eight sporozoites ... . 5. 



5 (6). Gregarine ovoid, with an epimerite ; [Porter. 



schizogony intracellular Merogregarinidse * 



6 (5). Gregarine conical, with pseudopodial 



processes along its base ; schizogony [& Dub. 



extracellular Ophryocystidae * Leg. 



7 (1). Gametocyst contains many oocysts . . 8. 



8 (15). Only one type of schizogony 9. 



9 (12). Schizogony intracellular 10. 



10 (11). Gregarine elongated, with longitudinal 



striations, and chromatic bodies at 

 the anterior end. Gametocyst con- 

 tains many oocysts, each containing 

 four or eight sporozoites Selenidiidae * Brazil t. 



11 (10). Gregarine elongate. Gametocyst con- 



tains sixteen oocysts, each containing 



eight sporozoites Lipotrophidae * Keilin. 



12 (9). Schizogony extracellular 13. 



13 (14). Gregarine vermicular. Gametocyst 



contains large number (about thirty) 



of oocysts, each containing eight [Dub. 



sporozoites Schizocystidse * Leg. & 



■)• According to Ray (1930) certain species of Selenidium do not 

 show any schizogony. 



