PROBOSCIDEA. 703 



divided into two parts by a constriction. In addition to tlie 

 short but broad caecum, there are two supplemental ca;ca 

 lower down on the intestine. The testes are abdominal. 

 Of the mamniEe, four are on the groin and two are axillary. 

 The placenta is zonary as in the Proboscidea and Carnivora. 

 No extinct forms are known. 



Sub-Order Proboscidea. 



This sub-order is now represented by two species of 

 elephant {Elephas). They occupy a somewhat isolated 

 position, though distinctly Ungulates. As regards skull, 

 proboscis, and teeth they are highly specialised, but their 

 limbs are of a generalised type. 



The elephants are confined to the Ethiopian and Oriental 

 regions. They feed on leaves, young branches, and herbage. 

 By means of the mobile proboscis they gather their food, 

 and they drink by filling the proboscis and then ejecting the 

 water into the mouth. 



The proboscis is a muscular extension of the nose, and 

 bears the nostrils at its tip. 



The skin is strong and the hair somewhat scanty. 



In the limbs, radius and ulna, tibia and fibula, are quite 

 distinct; the radius and ulna are fixed in a crossed position; 

 owing to the length of the humerus, and yet more of the 

 femur, elbow and knee are lower than usual ; the carpal and 

 tarsal bones have flat surfaces ; the feet are broad and bear 

 five hoofed toes embedded in a common integument. There 

 are no clavicles. 



The skull is very large, being adapted to support the 

 proboscis and tusks, and to afford a broad insertion for the 

 large muscles. In most of the bones there is during growth 

 an extraordinary development of air spaces, which com- 

 municate with the nasal passages. The nasal bones are very 

 short; the zygomatic arch (formed anteriorly by the maxilla, 

 medianly by the small jugal) is slender and straight. The 

 neck is very short. 



The dentition is unique. The two upper incisors or tusks 

 are mainly composed of solid ivory; the enamel is restricted 

 to the apex and soon wears off. As the tusks grow, their 

 roots sink through the premaxillae into the maxillae. There 

 are no canines nor premolars. The molars are very large. 



