410 QUESTIONS, PROBLEMS, AND SUGGESTIONS 



Name examples of mammals with these glands. Uses of each to the 

 mammal? Compare the glands of mammals with the glands of other chor- 

 date classes. Name internal glands of mammals. 



6. Take questions 7-27 under Birds, making necessary changes in the 

 questions to fit mammals. 



28. "Mammals are supposed to have originated from some early rep- 

 tihan animal and branched off long before the birds were evolved" 

 (American Animals, by Stone and Cram). State your idea of the make-up 

 of this primitive reptilian ancestor of mammals. 



29. Give your idea of a primitive mammal from which may have evolved 

 the mammahan orders of today. 



30. What, then, is the line of descent of chordates? Was it fish-like, 

 amphibian-hke, reptilian-Hke to primitive mammal, with birds as an off- 

 shoot from some reptilian-like ancestor? Wnat was the general structure 

 and make-up of a primitive chordate? (See Fig. 152.) 



31. Order I. Primitive Mammals. — Does the egg-laj'ing habit show 

 primitive condition? The "mammary pouch"? The cloaca? Hegner 

 says: "In certain respects, the skeleton agrees with that of the reptiles." 

 Would this show reptilian affinities? 



The Duck-bill. — Note its bill. For what use are the strong front toes? 

 Use of the duck-bill's tail? Habitat of the duck-bull? Why is this order 

 not a dominant one? 



32. Order II. — Show how these primitive mammals are in advance over 

 Order 1 in the condition of the young. Their peculiar mode of locomotion? 

 From the mode of life and the structure of this order, would it be a domi- 

 nant order if placed in contact with order Carnivoraf Why are the animals 

 of this order so restricted in their geographic distribuition? Why is the 

 opossum so widely distributed as compared with other members of this 

 order? 



33. Order V. Cetacea. — How do you account for the "blubber" of the 

 whale? The baleen? The hairless skin? Vestigial limbs? Horizontal 

 tail as the chief organ of locomotion? Was the whale ever a terrestrial 

 animal? If so, what changed it to an aquatic one? What is a whale? Its 

 commercial value as compared with the old days when whahng was a 

 buisness? 



34. Order VI. Ungulata. — What are the hoofs of this order? Horns? 

 Does any other order of mammals possess horns? Herbivorous or car- 

 nivorous? Special means of defense? Teeth in this order? Name un- 

 gulates domesticated by man. Uses? Ungulates of special curiosity? 

 (p. 343). 



Why are ungulates a dominant order? Name their chief chordate enemy; 

 their principal invertebrate enemies. 



35. Order VII. Rodentia. — Teeth of this order? Why no canines? 



