. Guide leaflet. hem as related. Here again is illustratedthe principle of convergence. Three unrelated types, the flying phalan-ger, the flying squirrel and the scaly tailed flying squirrel are exhibited inCase 29. Another, the taguan is to be seen in Case 28. Cursorial or Running Adaptations Cursorial adaptation implies ability to move not only rapidly butto sustain high speed for a long distance. To do this the limbs must belong and straight (81, 22) the joints must have the movements restricted BIOLOGY OF MAMMALS 35 chiefly to the fore and aft plane, and the fore and liintl hnihs must both
. Guide leaflet. hem as related. Here again is illustratedthe principle of convergence. Three unrelated types, the flying phalan-ger, the flying squirrel and the scaly tailed flying squirrel are exhibited inCase 29. Another, the taguan is to be seen in Case 28. Cursorial or Running Adaptations Cursorial adaptation implies ability to move not only rapidly butto sustain high speed for a long distance. To do this the limbs must belong and straight (81, 22) the joints must have the movements restricted BIOLOGY OF MAMMALS 35 chiefly to the fore and aft plane, and the fore and liintl hnihs must bothbe strongly developed. The adaptation is best if the point of eontactwith the ground is limited. Tlie horses (19) are possibly the most perfectexamples of this type of adaptation, though many of the artiodactyls(18, 60), particularly antelopes, are excellent runners. In the marsupialsthe Tasmanian wolf (52), is the best cursorial type while among thecarnivores, the cheetah and the dogs (53) are the best The skeleton of a kangaroo exhibiting the changed proportions of a leaping animal Saltatory or Leaping Adaptations Some animals that are defenceless and much preyed upon are modi-fied for great speed, though along lines that are not conducive to theconservation of energy. These animals progress by long bounds andsome use only the rear feet when moving most rapidly. In correlationwith this the animals have the hind legs greatly elongated. In some thefore legs are remarkably shortened. The tails of the bipedal animals areelongated and serve to counterbalance the body. The kangaroos (5), are the most widely known of the bipedal leap-ing animals, but other smaller forms such as the jerboas, (Jaculusorientalis, 14) are more highly modified. Other examples are thekangaroo rats (Dipodomys, 29, 51), the jumping shrews (Rhyncocyon, 7)and Tarsius (30). 36 AMERICAN MUSEUM GUIDE LEAFLET The giant dinosaur Tyranosaurus, exhibited on the fourth Hoor,though possessing the exaggerate
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