346 AN ELEMENTARY TEXT-BOOK OF BIOLOGY. 



but do not possess distinct interclavicle, epicoracoids 

 and coracoids, the last being represented by a process 

 of the scapula. There is no cloaca. The mammary 

 glands possess teats. 



Sub-Class #. Metatheria (Didelphia). Mammals 

 with inflected angle to the mandible and epipubic 

 (marsupial) bones. The oviducts are distinct in 

 typical cases, and there is not an allantoic placenta. 

 The female usually possesses a pouch. 



Order 1 . Marsupialia. Pouched animals : Kan- 

 garoo, opossum, wombat, &c. 



Sub-Class 3. Eutheria (Monodelphia). Mammals 

 in which the angle of the jaw is not inflected, and 

 there are no epipubic bones. The oviducts are more 

 or less fused, and there is an allantoic placenta. 



Orders of Eutheria. (1) Edentata Armadillo, sloth, &c. (2) 

 Ungulata (a) Artiodactyla, none of the digits bilaterally sym- 

 metrical Swine, hippopotamus, ruminants ; (b) Perissodactyla, 

 with a bilaterally symmetrical 3rd digit in each manus and pes 

 Tapir, rhinoceros, horse, &c. (3) Sirenia Dugong, manatee. 

 (4) Rodentia Rabbit, rat, porcupine, squirrel, guinea pig, &c. (5) 

 Proboscidea Elephant. (6) Hyracoidea Hyrax. (7) Insectivora 

 Hedgehog, mole, shrew, &c. (8) Cheiroptera Bats. (9) Carnivora 

 Dog, cat, bear, seal, &c. (10) Prosimice Lemurs. (11) Primates 

 (a) Arctopitheci, Marmozets ; (b) Platyrrhini, lower monkeys ; 

 (c) Catarrhini, higher monkeys (Cynomorpha) and man-like apes 

 (Anthropomorpha), see p. 338; (d) Anthropidae Man. 



PRINCIPLES OF DISTRIBUTION. 



Explanatory Theories. 



I. Theory of Special Creations, now abandoned. According to 

 it : 1. Organisms were created where now found. 2. The fauna 

 and flora of any particular region must be better adapted to it 



