384 GENERAL BIOLOGY 



Arrange the names by groups at the left hand, mam- 

 mals, birds, reptiles and amphibians. 



Fill out the table as far as possible from personal knowl- 

 edge and observation. For the balance consult reference 

 literature, or any other source of reliable information. In a 

 class of students this may be facilitated by division of 

 labor. If blanks still remain they should be useful as 

 indicating gaps in the knowledge of the local species. 



Such a table as the foregoing kept by the laboratory and 

 added to, year by year, by succeeding classes as knowledge 

 of the fauna increases, may grow into a most useful and reli- 

 able ready-reference chart. 



The record. — Complete the table so far as possible and 

 then write out briefly your own interpretation of the facts 

 contained in it. These facts should give rise to many legiti- 

 mate questions. Is there any clear relation between any 

 systematic group and any particular habit of feeding? of 

 locomotion ? What kind of habitat has the largest number 

 of species in its population and why? What habits are 

 shown by the smallest number of species and why ? Is there 

 any clear relation between size of the animals and habitat? 

 Between size and feeding habits? Between size and habits 

 of locomotion? etc., etc. 



Animal migrations are sudden shifts of place that de- 

 mand good powers of locomotion. When of irregular oc- 

 currence, as is usually the case with the migration of 

 mammals like the lemmings, and of insects like the Rocky 

 Mountain locust, they necessitate biological readjustment 

 in both the localities between which the migration occurs; 

 for the natural balance is disturbed in both places: but 

 when well established as a normal part of a mode of life, 

 as in the regular annual migrations of birds between their 

 summer and winter homes, the adjustment becomes per- 

 fected, not only as adjustment in place and time, but also 

 as adjustment between different places and seasons. 



