347] STUDIES ON GREGARINES-WATSON 137 



ACTINOCEPHALUS DYTISCORUM (Frantzius) Watson 

 [Figure 148] 



1848 Sporadina Dytiscorum Frantzius 1848:195 



1851 Gregarina Dytiscorum Diesing 1851 :12 



1863 Gregarina Dytiscorum Lankester 1863 :94 



1890 AncyropTwra uncinata Labbe 1899:28-9 



1916 Actinocephalus dytiscorum Watson (This paper) 



Actinocephalus : Sporonts robust. Ratio length protomerite : 

 total length :: 1 : 7; width protomerite : width deutomerite :: 1 : 1. 

 Protomerite broad and low, twice as wide as high, flattened in front. 

 Very slight constriction at septum. Deutomerite at septum same width 

 as protomerite in front in septum, retaining same width throughout 

 anterior half. Posterior half much narrower, tapering to a blunt point. 

 Cysts large, spherical, spores not known. 



Taken at , Germany. Host : Dytiscus sp. Habitat : Intes- 

 tine. 



This species is known from the drawings of Frantzius, one being 

 of an adult sporont ( ?) and the other of a cyst. Diesing gives as host 

 Dytiscus marginalis larva. Labbe regards the species as synonymous 

 with Ancyrophora uncinata Leger, from a similarity of the host, 

 Dytiscus. 



The sporont, however, has no resemblance to that of Leger 's species, 

 and, although the epimerite of the species in question is not known, it 

 seems to have an individuality. 



ACTINOCEPHALUS STELLIFORMIS Schneider 

 [Figures 67, 69, 73] 



1875 Actinocephalus stelliformis Schneider 1875:588-9 



1893 Actinocephalus stelliformis Pfeiffer 1893:5-11 



Actinocephalus: Dimensions not given. Ratio length protome- 

 rite : total length :: 1 : 4.5 to 1 : 8; width protomerite : width 

 deutomerite :: 1 : 1.4. Protomerite cylindrical, surmounted by a 

 broadly rounded anterior extremity; same width throughout posterior 

 half, width equal to length. Constriction at septum. Epimerite per- 

 sisting, a small globular structure surmounted by a corona of recurved 

 processes, each slender at the base, dilated and bifid at the distal ex- 

 tremity. Deutomerite widest above the middle, tapering to a long, 



