38 ILLINOIS BIOLOGICAL MONOGRAPHS [38 



sporozoites within the original host is one means the parasite has of 

 "holding its own" in Nature and reproducing at an enormous rate upon 

 certain occasions. This migration of the young gregarine through the 

 intestinal epithelium and production of a cyst from a single individual 

 resulting in schizogonic sporozoites may be due to a change of food in the 

 host animal unadapted to the parasite's requirements, to sickness of the 

 host, to a scarcity of food, to the time of the year, or to a natural phe- 

 nomenon occurring at stated intervals in the economy of the organism 

 itself. Or it may be due to some extraneous cause not mentioned. 



I am convinced that all the gregarines in the Crustacea will again 

 come under one family head and that the Aggregatidae, the oldest known 

 group, will be restored to its position among the gregarines. The Poro- 

 sporidae and Cephaloidophoridae will of necessity be dropped. But in 

 the meantime, until much more work on the crustacean parasites shall 

 have been done and complete life-histories become the rule rather than the 

 exception, the present group headings must remain. 



Type Genus CEPHALOIDOPHORA Mawrodiadi 1908: 101 

 Intestinal parasites of Crustacea. Characters of the family. 



CEPHALOIDOPHORA CONFORMIS (Diesing) Leger and Duboscq 



[Figures 66 and 75] 



1787 Unnamed Cavolini 1787: 169 



1810 ? Distome Rudolphi 1810: 287 



1819 ? Distome Rudolphi 1819: 197 



1851 Gregarina conformis Diesing 1851:15 



1859 Gregarina conformis Diesing 1859: 735 



1863 Gregarina conformis Lankester 1863: 95 



1885 Gregarina conformis Frenzel 1885:579 



1899 A ggregata conformis Labbe" 1899:6 



1903 Aggregala conformis Minchin 1903: 331 



1907 Frenzelina conformis Leger and Duboscq 1907: 773 



1908 Frenzelina conformis Leger and Duboscq 1908: 99 



1909 Frenzelina conformis Leger and Duboscq 1909: 733 

 1909 Frenzelina conformis Leger and Duboscq 1909a: 113 

 1911 Frenzelina conformis Sokolow 1911: 280 

 1911 Cephaloidophora conformis L^ger and Duboscq 1911: lix 

 1913 Aggregate conformis Ellis 1913: 264 



(Frenzel) Sporonts associated in pairs, not more than two, irregularly 

 cylindrical, tapering slightly, well-rounded posteriorly. Often a slight 

 shoulder exists. Protomerite broadly dome-shaped, slightly constricted 



