COCCIDIIDEA 135 



several speciesparasiti c in the seminal vesicles of earthworms. Many 

 other genera parasitic in Echinodermata, Tunicata, Arthropoda, etc. 



Tribe 2.Cephalina. With an epimerite, either temporarily or 

 permanently, in the trophic phase. Usually septate (except Dolio- 

 cystidcv). Many families, genera and species. Common in the digestive 

 tracts of insects. E.g. : Gregarina, with several species, Gregarina 

 ovata in the earwig, Gregarina blattarnm in the cockroach, Stylorhyn- 

 chus in beetles, Pterocephalus in centipedes, etc. 



Sub-order II. Schizogregarinea, with schizogony. 



Tribe i. Endoschiza} With schizogony occurring in the intra- 

 cellular phase, e.g., Selenidium (from Annelida and Gephyrea), Mero- 

 gregarina (from an Ascidian). 



Tribe 2. Ectoschiza. In which the schizont is free, and schizogony 

 is extracellular, e.g., Ophryocystis (from Blaps, a beetle), and Schizo- 

 cystis (from Ceratopogon larva). 



Order. Coccidiidea. 



Hake (1839) first saw the organisms now termed Coccidia during his investigations 

 on the so-called coccidial nodules of rabbits. The opinions as to the nature of these 

 peculiar formations were very diverse. The discoverer considered them to be a sort 

 of pus corpuscle ; Nasse (1843) to k them for epithelial cells of the biliary passages, 

 others for helminthes, especially the ova of trematodes (Dujardin, Kiichenmeister, 

 Gubler, etc ). Remak (1845) was the first to draw attention to their relation to the 

 Psorospermia (Myxosporidia), and this investigator found them also in the small 

 intestine and vermiform appendix of rabbits. Lieberkiihn (1854), who examined not 

 only the coccidia of rabbits, but found similar forms in the kidneys of frogs, likewise 

 called them definitely psorosperms. To differentiate Miiller's psorosperms, which are 

 found in fishes, from those of rabbits, etc., the latter were called egg-shaped psoro- 

 sperms (Eimer), until R. Leuckart (1879) named them Coccidia and placed them in 

 a group of the Sporozoa analogous to that of the Gregarinida, Myxosporidia, etc. 

 Numerous works confirmed the occurrence of coccidia, not only in all classes of 

 vertebrate animals, but also in invertebrates (Mollusca, Myriapoda, Annelida, etc.). 

 A large number of genera and species have in the course of time been described which 

 inhabit the epithelium of the intestine and its appendages for choice, but are also 

 found in other organs (kidneys, spleen, ovaries, vas deferens, testicles). Some also 

 live in the connective tissue of various organs, more particularly of the intestine. 



The knowledge of the development of the coccidia was of particular importance 

 in determining their classification. By means of encysted coccidia from the liver of 

 rabbits, Kauffmann (1847) first confirmed the fact that the cyst, which was partly or 

 entirely filled with granular contents, divided into three or four pale bodies (fig. 71) 

 after a long sojourn in water. Lieberkiihn observed the same process in the host in 

 the case of the coccidia of the kidney of the frog. Stieda (1865) studied more minutely 

 the changes that occur within the encysted coccidia of the liver of rabbits after the 

 death of the host. He discovered that the bodies now known as "spores" were 

 ova] formations pointed at one pole, and surrounded by a delicate membrane, which 

 exhibited a certain thickness at the pointed extremity and enclosed a slightly bent 

 rodlet, expanding at either end into a strongly light-refracting globule ; a finely- 

 granular globule was present in the middle of the spore. Waldenburg (1862) saw the 



1 See Fantham (1908), Parasitology -, i, p. 369. 



