GEEGAEI^'ID^. 49 



CHAPTER VI. 



GREGAPJNID^. 



1. Habit. — 2 Form and Structure. — 3. Development. — 4. Classi- 

 fication. — 5. Psorospermi^e. 



1. Habit. — Dufour was the first to designate 

 under the name of GregavincB a group of micro- 

 scopic organisms which differ remarkably in habit 

 from the preceding Protozoa, since they have 

 hitherto been only known to occur as parasites 

 wdthin the bodies of other animals, more especially 

 those belonging to the sub-kingdom Annulosa. 



2. Forsii a;id ^trtic*l?ire. — The form of the 

 body varies, being, in most cases, more or less 

 ovate. In many Gregarinidce it is marked by 

 clefts or strictures which, with their corresponding 

 internal septa, divide it into two or more segments 

 {Jig. 11). In some, a sort of process projects 

 from one end of the body, and this is frequently 

 furnished at its extremity with a number of re- 

 flexed booklets, by means of which it is supposed 

 that these animals are enabled to attach them- 

 selves more firmly to those surfaces whereon they 

 are usually found (c^). 



Anatomically, the Gregarinidce are found to 

 consist of a transparent membrane enclosing a 

 mass of granular contents, in the interior of which 

 a nucleus, surrounded by a well defined clear 

 space, may in most cases be observed (c, d, f ). 



The Gregarinidce are colourless, and would 

 appear to possess a limited amount of locomotive 

 power. 



E 



