230 THE SPOROZOA 



FAMILY 1. ASPOROCYSTIDAE, Leger (Tribe Monosporea, A. Schneider). 

 No sporocysts are formed within the oocyst ; the sporozoites are naked 

 (gymnospores). 



Genus 1. Eimeria, A. Schn., 1875 (Legerella, Mesnil, 1900). With 

 the characters of the family. 



The genus Eimeria was founded by Aime Schneider for the 

 Gregarina falciformis described by Eimer (1870) from the intestine 

 of the mouse. The diagnostic generic character was the absence of 

 sporocysts. Several other species were afterwards added by Schneider 

 and others to the genus. The rapid advances that have been 

 made within recent years in our knowledge of the life - histories of 

 Coccidia have shown that nearly all the species of Eimeria are nothing 

 but the schizogonous generations of Coccidia belonging to other genera 

 and species. Thus the type species, E. falciformis of the mouse, becomes 

 Coccidium falciforme ; E. schneideri, Butschli, from Lithobius, is the 

 schizont of Adelea ovata ; while E. schneideri, Schneider non Butschli, 

 appears to be that of Coccidium lacazei (Labbd). E. nepae is probably 

 identical in like manner with Barrowssia ornata from the same host. In 

 the light of these facts, it appeared, until recently, extremely probable 

 that the name Eimeria was about to become a women nudum, a fate which 

 has already overtaken the " Eimerian " genera Pfeifferia seu Pfeifferella, 

 Labbe" ; Karyophagus, Steinhaus ; Cytophagus, Steinhaus ; Acystis, Labbe 

 (founded to include the two foregoing) ; Gonobia, Mingazzini ; Molybdis, 

 Pachinger ; and Cretya, Mingazzini. 



Quite recently, however, it has been discovered by Le*ger [47] and 

 Bonnet-Eymard [31] that one species, at least, of Eimeria has claims to 

 independent recognition. E. nova, A. Schn., from the Malpighian tubules 

 of Glomeris has been thought to be the Eimerian stage of Cyclospora 

 glomericola, A. Schn., from the same host ; but Glomeris guttata in Provence, 

 and G. ornata in the Dauphin e, are infected with the Eimeria, but not 

 with the Cyclospora. Examination of the Eimeria shows further that it 

 has a typical alternation of generations ; schizogony, with differentiated 

 male and female schizonts, as in Adelea ovata, is followed by sporogony, 

 with the formation of a zygote which breaks up within a resistent oocyst 

 into thirty or forty naked sporozoites, arranged side by side, or in a 

 twisted bundle. 



Eimeria nova remains, therefore, an independent species, the only 

 one 1 at present contained in the genus after subtraction of those which 

 are merely schizonts of other species. The true Eimeria is easily 

 distinguished from the false by the fact that its naked sporozoites are 

 enclosed in a resistent oocyst, whereas in schizogony there is no cyst- 

 envelope of any sort enclosing the merozoites. 



should be Eimeridae (or Leger ell idae) ; the Disporocystidae should be Isosporidae ; 

 the Tetrasporocystidae should be Coccididae (or Eiineridae) ; and the Polysporo- 

 cystidae should be Klossidae. 



1 Since this was written Cuenot [32] has described another species of Eimeria, 

 under the name Legerella testiculi, which is parasitic in the testis of Glomeris mar- 

 ginata, and therefore occurs only in one sex of the host. In this form precocious 

 association occurs between a macrogametocyte and one or two microgametocytes, 

 as in Adelea ovata. 



