THE GREGARINID^. 



87 



or elongated oval bodies, sometimes divided by constrictions 

 into segments. Occasionally, one end of the body is pro- 

 duced into a sort of rostrum, which may be armed with re- 

 curved horny spines. 



In the ordinary Gregarmce, the body presents a denser 

 cortical laver (ectosarc) and a more fluid inner substance 

 (endosarc), in which last the endoplast (nucleus) is imbed- 

 ded. The presence of contractility is manifested merely by 

 slow changes of form, and nutrition appears to be effected by 

 the imbil)ition of the fluid nutriment, prepared by the organs 

 of the animals in which the Gregarbiui are parasitic. There 

 is no contractile vacuole. 



The Gregaririm have a peculiar mode of multiplication, 

 sometimes preceded by a process which resembles conju- 

 gation. A single Gregarina (or two which have become 

 applied together) surrounds itself with a structureless cyst. 



Fig. 7.— .4, Gregarina of the earttiworm (after Lieberkiihnl ; B. encvPted ; r, D, 

 contents divided into pseud o-navicellae ; E, F, free pseudo-navicella: , G, H. free 

 amcebiform contauts of tLie latter. 



Tlie nucleus disappears, and the protoplasm breaks up (in a 

 manner very similar to that in which the protoplasm of a 



