SUB-KINGDOM I. PROTOZOA. 



3-S 



the rank of a " sub-kingdom." It should not be forgotten, 

 however, that this is a provisional arrangement, and that 

 future researches may demonstrate the propriety of a redis- 

 tribution of the somewhat heterogeneous group of organisms 

 at present included under this head. Subjoined is a brief 

 synoptical view of the primary divisions of the animal and 

 vegetable kingdoms, with the characters of the leading groups 

 comprised in each. 



ANIMAL KINGDOM. 

 SUB-KINGDOM I. PROTOZOA. 



Animal, simple or compound, usually very minute. Body composed 

 of the contractile, structureless, albuminoid substance termed " sar- 

 code ; " showing no composition out of definite segments ; having no 

 nervous system, no regular circulatory system, no definite body-cavity, 

 and either no digestive apparatus, or at most a mouth and short gullet. 

 Reproduction sexual and non-sexual (fig. 7). 



Fig. 7. Protozoa. A Gregarine ; B Rhizopod ; C Infusorian. 



CLASS A. GREGARINIDA. Protozoa which live parasitically in the 

 interior of insects and other animals, which are destitute of a mouth, and 

 have no power of throwing out prolongations or processes of the body- 

 substance ("pseudopodia"). 



CLASS B. RHIZOPODA (Root-footed Protozoa). Protozoa which are 



