PART II. 



CHAPTER VII. 



6- UB-KINGD OM I. PRO TOZOA . 



SUB - KINGDOM I. PROTOZOA. Animal simple or composite, 

 generally of very minute size, composed of a structureless, jelly-like, 

 albuminoid substance (termed " sarcode"\ showing no composition 

 out of definite parts or segments, having no definite body -cavity, 

 presenting no traces of a nervous system, and having either no ali- 

 mentary apparatus, or but a very rudimentary one. 



TABLE OF THE DIVISIONS OF THE PROTOZOA. 



CLASS A. GREGARINID^E. Parasitic Protozoa, which are destitute of a 

 mouth, and do not possess the power of emitting processes of their body- 

 substance (pseudopodia). 



CLASS B. RHIZOPODA. Protozoa, which are destitute of a mouth, and 

 have the power of emitting extensile and contractile processes of the body- 

 substance (pseudopodia). 



Order I. Monera. Ex. Protogenes. 

 Order 2. Anixbea. Ex. Amoeba. 

 Order 3. Foraminifera. Ex. Nummulites. 

 Order 4. Radiolaria. Ex. Haliomma. 

 Order 5. Spongida. Ex. Spongilla. 



CLASS C. INFUSORIA (Infusorian Animalcules). Protozoa mostly with 

 a mouth, and rudimentary digestive canal ; destitute of the power of emit- 

 ting pseudopodia; furnished with vibratile cilia or contractile filaments; 

 the body usually with a distinct cuticle covering a layer of firm sarcode. 



Regarded palaeontologically, we may eliminate from the Pro- 

 tozoa the entire class of the Gregarinidce, with the Rhizopodous 

 orders of the Monera and Amosbea, no trace of the past exis- 

 tence of which has yet been obtained, or, from their soft-bodied 

 nature, is ever likely to be. For all practical purposes the 

 same may be said of the large and universally-distributed class 

 of the Infusorian Animalcules. Some of these, however, possess 

 horny or membranous cases which might possibly be preserved 

 in a fossil state ; and it has been alleged that the genus Peri- 



