XXV] CLASSIFICATION 725 



Family 6. Antilocapridae. 



Selenodontia with branched horns which are outgrowths 

 of the frontal covered with a horny sheath. This sheath is 

 shed annually but not the core of the horn. Four com- 

 partments in the stomach. 



Ex. Antilocapra. 



Order VII. Sirenia. 



Aquatic Eutheria, with limbs and tail as in the Cetacea : 

 the cranium is cylindrical and the teats pectoral. 

 Ex. Manatus, Halicore. 



Order VIII. Rodentia. 



Eutheria with one large pair of chisel-shaped incisors in 

 each jaw growing throughout life and no canines. The 

 Rodentia walk on the whole surface of the last joint of the 

 digit, not on the extreme tip as do the Ungulata : the nails are 

 blunt but not usually hoof-like. 



Sub- order 1. Duplicidentata. 



Rodentia in which there is a second pair of rudimentary 

 incisors in the upper jaw. 

 Ex. Lepus. 



Sub-order '2. Simplicidentata. 



Rodentia in which there is only one pair of incisors in the 

 upper jaw. 



Ex. Sciurus, Tamias, Mus, Fiber, Arvicola, Muscar- 

 dinus, Castor, Erethizon, Hystrix, Cavia. 



Order IX. Cheiroptera. 



Eutheria in which the fore-limb is converted into a wing, 

 the hand being greatly enlarged and the fingers elongated in 

 order to support the wing-membrane ; the leg small and the 

 knee-joint rotated backwards : teeth and brain resembling 

 those of the Insectivora. 



Ex. Vespertilio, Vesperugo, Ehinolophus, Xantharpyia. 



Order X. Primates. 



Eutheria with long limbs, the brachium and femur not being 

 buried in the body : five digits in each limb, some of them 



