I 



CLASS MAMMALIA 645 



Order 12. Proboscidea. — Elephants. — Ungulata with 

 long, prehensile proboscis ; incisors form tusks; 

 molars very broad. Examples: Elephas, Asiatic ele- 

 phant; Loxodonta, African elephant (Fig. 540). 



Order 13. Sirenia. — Sea-cows. — Aquatic Eutheria of 

 the ungulate type; tail with horizontal fin; fore limbs 

 fin-like; hind limbs absent. Examples: Halicore, 

 dugong; Manatus, manatee (Fig. 541). 



Order 14. Hyracoidea. — Hyraces or Coneys. — Small ro- 

 dent-like mammals, with short ears and reduced tail; 

 fore limbs with four digits; hind limbs with three digits. 

 There is a single living genus, Procavia, and about 

 eighteen species, in Africa. One species, P. syriaca, 

 reaches Syria; it is the coney of the Bible. 

 Section D. Cetacea. — Whales and Dolphins. — Aquatic 

 mammals probably derived from the Unguiculata or 

 Ungulata. 



Order 15. Odontoceti (Denticeti). — Toothed Whales. 

 Cetacea with teeth, at least on the lower jaw; no 

 whalebone. Examples: Dclp/iinus, dolphin (Fig. 542); 

 Phocoena, porpoise; Grampus, grampus. 



Order 16. Mystacoceti. — Whalebone Whales. — Cetacea 

 without teeth in adult; mouth provided with plates 

 of whalebone. Examples: Baloenoptera, fin whale; 

 Balcena, right whale. 



3 A Review of the Principal Orders and Families of 



Living Mammals 



Order Monotremata. — Egg-laying Mammals. — The Mono- 

 tremes are primitive mammals confined to Australia, New 

 Guinea, and Tasmania. Their most conspicuous peculiarity is 

 their egg-laying habit, since they are the only mammals that 

 reproduce in this way. The two oviducts do not unite to form 

 a vagina, but open into a cloaca along with the intestine and 

 urethra, as in birds and reptiles (hence the term Monotremata: 



