14 ANIMAL LIFE 
canal* of crayfishes and centipeds and certain insects. 
Gregarina is a parasite, living at the expense of the host 
in whose body it lies. It has no need to swim about quickly, 
Fre. 9.—Gregarinide. A, a Gregarinid (Actinocephalus oligacanthus) from the intes- 
tine of an insect (after STEIN); B and C, spore forming by a Gregarinid (Coc- 
cidium oviforme) from the liver of a guinea-pig (after L—ucKaRT); D, E, and 
F, successive stages in the conjugation and spore forming of Gregarina poly- 
morpha (after KoELLIKER). 
and hence has no swimming cilia like Paramecium and 
the young Vorticella. It does need to cling to the inner 
wall of the alimentary canal of its host, and the body of 
some species is provided with hooks for that purpose. The 
* Specimens of Gregarina can be abundantly found in the alimen- 
tary canal of meal worms, the larve of the black beetle (Tenebrio moli- 
tor), common in granaries, mills, and brans. “Snip off with small 
scissors both ends of a larva, seize the protruding (white) intestine with 
forceps, draw it out, and tease a portion in normal salt solution (water 
will do) on a slide, Cover, find with the low power (minute, oblong, 
transparent bodies), and study with any higher objective to suit,”— 
Murpacn, 
