156 The Mastigophora 



colonies are composed of two or four circlets of flagellates so arranged 

 that one organism does not lie directly above another. Individual flagel- 

 lates have two or four flagella. Daughter colonies are produced by fission 

 of any member of a colony within its original membrane. In contrast to 

 the Volvocidae, a plakea stage is not formed in development. 



The family includes the following genera: Pascheriella Korshikov (164; Fig. 4. 30, B), 

 Pyrobotrys Arnoldi (Chlamydobotrys Korshikov) (256; Fig. 4. 30, A), Spotidylotnorum 

 Ehrenberg (206. 207; Fig. 4. 30, D). 



In Corone Fott (Fig. 4. 30, C), the widely separated flagellates are joined by tough 

 strands. Since this type of organization differs from that of typical Spondylomoridae, 

 perhaps a new family Coronidae should be recognized, as suggested by Fott (84). 



Fig. 4. 30. A. Pyrobotrys (Chlamydobotrys) squarrosa (Korshikofl), xl050 

 (after K.). B. Pasclieriella tetras Korshikotf, xl575 (after K.). C. Corone bo- 

 hemica Fott; length of colony (without flagella), 35-50^; flagella (one pair 

 shown full length) measure 35-40^ (after F.). D. Spondylomorum quater- 

 narium Ehrbg. (after Stein); colonies reach lengths of 50-70yn. 



Family 6. Volvocidae. This group differs from the Spondylomoridae in 

 two major features: colonial organization is maintained by a matrix, and 

 a plakea stage (Fig. 4. 32, C) appears in the development of a young 

 colony. 



