APPENDIX 181 



SHORT DEFINITIONS OF THE PRINCIPAL GROUPS OF THE 

 ANIMAL KINGDOM 1 



Subkingdom I. PROTOZOA. Single-celled animals; aquatic, 

 and mostly microscopic. 



Class I. Rhizopoda. Protozoans with retractile pseudopodia. 



Order 1. LOBOSA. Rhizopods with shell or naked, and usually 

 with blunt pseudopodia. Ex. Amoeba. 



Order 2. FORAMINIFERA. Marine rhizopods with calcareous 

 shell perforated by pores. Ex. Globigerina. 



Order 3. HELIOZOA. Freshwater rhizopods with silicious 

 skeleton. Ex. Actinospherium. 



Order 4. RADIOLARIA. Marine rhizopods with silicious skele- 

 tons. Ex. Polycistina. 



Glass II. Sporozoa. Protozoans which are internal parasites and 

 without organs of locomotion. Ex. Gregarina. 



Class III. Flagellata. Protozoans with one or more vibratile 

 flagella. Ex. Euglena. 



Class IV. Infusoria. Protozoans with cilia or with sucking 

 tentacles. 



Order 1. CILIATA. Ciliate infusorians. Ex. Parainecium. 



Order 2. SUCTORIA. Sessile infusorians with sucking tenta- 

 cles. Ex. Acineta. 



Subkingdom II. METAZOA. Many-celled animals, usually with 

 specialized organs and tissues. 



Division I. GASTROZOA (COELENTERATA). Eadiate animals 

 with but a single, although sometimes branched, internal cavity ; 

 with no body-cavity (coelom) ; animals of simple structure, which 

 do not develop beyond the condition of the gastrula. 



Type I. SPONGIARIA. Sessile, usually colonial, gastrozoans 

 without special organs or tissues ; body-wall pierced by numerous 

 pores or canals. 



Class I. Calcarea. Sponges with calcareous spicules and of sim- 

 ple structure. 



1 These definitions are not meant to be exhaustive, but simply to characterize 

 the various groups in the fewest possible words. 



