6 A SYNOPSIS OF ANIMAL CLASSIFICATION. 



Order 4. Heliozoa Usually fresh-water forms; mostly 



spherical in shape, with silicious 

 spicules. 



X Aciinophrys, Clathrulina. 



Class II. INFUSORIA Cell-wall present, furnished with 



cilia or with knobbed tentacles. 



Order i . Ciliata Body ciliated ; usually locomotive ; 



a few sessile forms. 



Sub-order i . Holotricha Cilia uniformly covering the body. 



X Paramcecium. 

 Sub-order 2. Heteroiricha . . .Cilia in patches, and often of dif- 

 ferent lengths. X Stentor. 



Sub-order 3. Peritricha Cilia in a ring around the mouth. 



X Vorticella, Epislylis. 

 Sub-order 4. Hypoiricha .... Cilia only underneath ; creeping 



forms. X Stylonychia. 



Order 2. Suctoria Certain areas of body prolonged 



into attenuated tentacles tipped 

 with adhesive knobs. x Acineta. 



Class III. MASTIGOPHORA Cell -wall present ; move by one or 



more flagella ; solitary and colo- 

 nial forms. 

 Order i . Nudoflagellata .... Simple monads, solitary or colonial. 



X Cercomonas. 

 Order 2. Choanoflagellata . .Collared monads, often colonial. 



X Codosiga. 

 Order 3. Cilioflagellata. . . .Mostly marine forms, with siliceous 



exoskeleton. 



X Ceratium, Peridinium. 

 Order 4. Cvstoflagellata. ...Large marine forms, with reticu- 

 lated endoplasm. x Noctiluca. 

 Supplementary Order. VoLVoaNA; Large, spherical colonies contain- 

 ing specialized macro- and micro- 

 zooids for reproduction. May 

 probably be classed as plants. 



Many of the lower plants are, at least in certain stages, typical 

 Flagellates, and thus the plants and animals come in contact at about 



