158 NATURE-STUDY REVIEW [14:4— April, 1918 



Fins. i. Dorsal: equal to or shorter than anal fin where joined to body; 

 single, or partly or wholly divided; 

 soft rays only or both spines and soft rays; • 

 dorsal fin formula. D 7 or 8. 



2. Adipose fin: present or absent ; free or joined to tail fin. 



3. Caudal or tail fin: sketch its shape accurately. 



4. Pectorals: armed with a spine or soft rays only. 



5. Ventrals or pelvics: abdominal or thoracic in position. 

 Lateral Line: continuous, broken or absent; straight, curves upward or 



downward. 



Scales: large, medium, minute, wanting; smooth or rough. (To determ- 

 ine them, pass finger over side of body from tail towards head). 

 Color and Markings. 



[ back Dusky. 



1 . General ground color \ sides Bluish iridescence 



{ under parts Silvery. 



J location Sides 1 In young of both 



2. Longitudinal stripes <{ extent Cheek to tail \ sexes 



[ color Black j 



[ location 



3. Vertical bars \ extent None. 



[ color 



4. Spots, blotches, mottlings, brilliant coloration.. 



Location and color Black blotch in front lower angle of dorsal fin. 



Sex Differences. 



1. Pearl organs on male. Where? On head at breeding time only. 



2. Conspicuous colors or markings on male. Where? Reddish on under 



fins and belly at breeding time. 

 Food consists of what? 



Aquatic insects, small crayfish, young fishes and occasionally algae. 

 Eggs. Where are they deposited? 



In a depression in gravel shoals running water. 

 Does this fish guard eggs and young? 

 No parental care. 

 Miscellaneous. 



In order to illustrate the third part of the program — classification 

 and key building — let us suppose that we have outlines filled out 

 for the following: 



Horned Dace Brook Trout 



Black-nose Dace Sunfish 



Sucker Yellow Perch 



Catfish Stickleback 



