GREGARINIDJE 



83 



the cyst-wall. These are the sporoducts through which, in the ripe 

 cyst, the spores are evacuated, the canals becoming everted in the 

 process. 



In place of the Gregarines of the mealworm, the following varie- 

 ties may be used for observation purposes : G. blattarum, which is very 

 similar and is found with great frequency in the common cock- 

 roach ; or G. ovata, which is egg-like in shape and compact in 

 structure, and is found in the earwig, Forficula auricularia. In 

 these varieties the epimerite, 

 which is placed in front of 

 the protomerite and by means 

 of which the young Gregarines 

 fix themselves in the intestinal 



wall of their host, is button- Q| j 



shaped and only slightly de- 

 veloped. Interesting modifica- 

 tions in the structure of the 

 epimerite are seen in the 

 varieties of Gregarine which 

 inhabit the intestinal tracts of encysting 

 of Lithobius and of the larvae 



of Agrion. Those found in the Agrion larva are particularly well 

 worth studying. These larvse are prevalent in our fresh-water spaces ; 

 they are easily recognized by their slender form and by the possession 

 of three free, leaf-shaped tail-gills. 



The study of fresh material should be supplemented by the 

 preparation of cover-glass specimens and of sections. In transverse 

 sections of the adult parasite, the cuticle w r ill appear serrated at the 

 edge. This is due to the longitudinal striation, so eminently charac- 

 terestic of the order. The circular muscle-fibrillae are seen in super- 

 ficial longitudinal sections. Sections from the whole intestine are 

 useful in identifying species ; they also show the manner in which 

 the Gregarines attach themselves to the intestinal wall of their host. 1 





PIG. 25. Grcfjarina blattarum in the process 

 (After Biitschli, from Braun.) 



Note : Aggregata. 



The A^pvoatii are a class of the Telosporidia. They resemble 

 the CWeuliii in possessing no cuticle and no definite separation of 

 ecto- from ondoplasm, but in all other ways they approximate very 



1 A more detailetl inscription of the cytology of the Gregarines of the mealworm 

 is given bv S. Kuselmke^ itsclu IVobnehtun^en liber vegetative, degenerative u. 

 germinative Vor^ui^e bei den (.ire^mnen des Mehl\\ urindarmes,'' Arch, f Protitttrti- 

 A-wnrfr, snppl. i. 1W7. pp- ^O'J-'J-W. 



