SPOROZOA IN GENERAL 277 



Subclass II. NEOSPORIDIA 



Order i. myxosporidia 

 Order 2. microsporidia 

 Order 3. sarcosporidia 



GREGARINES 



The gregarines are among the simplest of the sporozoa and are 

 easily obtained for study since they are common parasites in 

 the digestive tract and body cavity of insects and earthworms. One 

 of the easiest types to obtain is Monocystis which occurs in the 

 seminal vesicles of the earthworm. The life-cycle of Monocystis 

 is fairly well known but many points regarding it still remain 

 obscure and the method of transmission of this type of gregarine 

 needs further investigation. 



Cephaline gregarines, that is gregarines with an epimerite or 

 "head," are abundant in insects and can be obtained easily from 

 the intestine of grasshoppers, cockroaches or meal worms. There 

 are a number of problems concerning the life-cycle and activities 

 of the cephaline gregarines, for example, their method of locomo- 

 tion and the significance of the union of sporonts end to end, a 

 condition known as syzygy. A number of very complicated life- 

 cycles have been described among the schizogregarines, a group 

 of gregarines including a period of schizogony in their life-cycle. 

 Certain stages are passed in one host such as a snail and others in 

 another host such as a crab. Confirmation is needed of certain of 

 these life-cycles. 



COCCIDIA 



CocciDiA are likewise easy to obtain for study. Perhaps those 

 that occur in rabbits are most prevalent. A large proportion of 

 these animals are infected, and unsegmented oocysts are usually 

 present in their feces ; the segmentation of these can be observed 

 if material is placed in a five per cent aqueous solution of potassium 

 bichromate, which inhibits the growth of bacteria. Other labora- 

 tory and domesticated animals such as rats, cats, dogs and chickens 

 are frequently infected with coccidia. In fact it is often difficult to 

 prevent infection with species belonging to this order. The common 

 species that occurs in the rabbit belongs to the genus Elmer ia 

 in the oocysts of which there are four spores, in each of which 

 two sporozoites develop. Species belonging to the genus Isospora 

 may be obtained from cats and dogs ; in their oocysts two spores 



