ELEMENTS OF COMPARATIVE ZOOLOGY, 



INTRODUCTION. 



EVERY true teacher must have his own methods, but 

 some suggestions as to the way in which this book is 

 intended to be used may be of value. In the first place, 

 the laboratory 7 woik is regarded as most important, since 

 through it the student is trained in observation a train- 

 ing utterly lacking in all the non-scientific studies of the 

 school curriculum; and also since by it he acquires an 

 autoptic knowledge of the animals studied. It is believed 

 that every point mentioned in the laboratory directions 

 can be made out by students in the high-school grades. 



In case the time be not sufficient to cover all the forms 

 described, some may be omitted, but the writer thinks 

 that any course should include at least the dogfish, teleost, 

 frog, rat, crayfish, grasshopper, earthworm, clam, star- 

 fish, sea-urchin, and sea-anemone. 



Each student should make all the drawings called for. 

 Drawing the object seen is one of the greatest aids to 

 observation, and every pupil, no matter how lacking in 

 artistic ability, can make intelligible sketches of all points 

 demanded. These sketches have great value for the 

 teacher, since by their aid one can see at a glance any 



