26 LABORATORY STUDIES UPON TYPIC ANIMALS 



(3) Anj^ commensalism or symbiosis? 



(a) With what animal? 



(b) Effect upon each? 



(4) Is this animal diurnal, crepuscular, or nocturnal in 



its activities? Why? 



21. MultipHcation. 



(1) Is this animal hermaphroditic? 



(2) Is it dimorphic, trimorphic, or polymorphic? 



(3) Does it have alternation of generations? 



(4) Is its multiplication sexual, asexual, or both? 



22. The Young. 



(1) Number in a brood? 



(2) Number of broods in a year? 



(3) Are the young precocial or altricial? 



(4) Time required to reach growth or maturity? 



(5) Average length of life of this species? What relation 



between the growing period and the length of life? 



23. Activities Due to Environment. 



(1) Does this animal migrate, hibernate, or remain active 



in winter? 



(2) If it hibernates, how or in what does it hibernate? 



(3) If it migrates, to what place or conditions does it go? 



(4) Does it go singly, or with others of its kind? 



(5) Does it migrate, estivate, or remain active in summer? 



If it migrates, to what place does it go? Why? 

 When does it go? When return? 



24. Geographic Distribution. 1 State as accurately as possible 

 the geographic distribution of this family or species of animals. 



(1) Do any of its habits or features of structure vary in 



different localities? How? Why? Examples. 



(2) Name some of the means of dispersal of this animal. 



(3) Name the barriers to dispersal. Why are these con- 



ditions barriers to the dispersal of this particular 

 animal? 



25. Geologic Distribution.^ 



(1) In what era did its Branch and Class appear? 



(2) Are the individuals of this class more numerous than in 



former geologic eras? 



(3) Are they more or less highly developed? 



^See Daugherty's "Economic Zoology." ^See a good geology. 



