KEY TO PHYLA 21 



14 (15) Body not segmented, covered with cuticula. phylum 



NEMATHELMiNTHES (see page 22) 



15 (7) Body segmented 16 



16 (19) AVithont jointed appendages; worm-like 17 



17 (18) With bristles arranged on certain segments (if no bris- 



tles then a sucker on each end of body) ; without tracheae 

 or spiracular openings, never with large tufts of bristles at 

 one end of body, phylum Annelida (see page 22) 



18 (17) With tracheae and tracheal gills or spiracular open- 



ings; often with large tufts of bristles at one end of body; 

 with a head well differentiated and always with some form 

 of antennae and mouth parts, phylum arthropoda, class 

 iNSECTA (larvae) (see page 23) 



19 (16) With jointed appendages at least on extreme anterior 



segments, phylum arthropoda (see page 23) 



I. Phylum Protozoa 



1 (2) No locomotor structures in adult age; parasitic 



CLASS SPOROZOA 



2 (1) Special structures for locomotion 3 



3 (4) Temporary lobes (pseudopodia) protruded for locomo- 



tion CLASS RHIZOPODA 



4 (3) Permanent processes (cilia or flagella) from the surface 



of body for locomotion , 5 



5 (6) Numerous short protoplasmic processes (cilia) 



CLASS CILIATA 



6 (5) Small number of long thread-like protoplasmic processes 



(flagella) class mastigophora 



II. Phylum Porifera 



The Phylum Porifera is represented in fresh water by sev- 



