158 BULLETIN 5(3, UNITED STATES NATIONAL MUSEUM. 



Order UNGULATA. 



HOOFED ANIMALS. 



Teeth lieterodont. and diphyodont. Crowns of molars broad with 

 tul)erculated or ridged surfaces. No clavicles. Toes with blunt, 

 broad nails, or in the majority of cases with hoofs, more or less in- 

 closing the ungual phalanges. The testes descend into a scrotum. 

 There is never an os penis. The uterus is bicornuate. The mammae 

 are usually few and inguinal, or may be numerous and abdominal {as 

 in Siniui), but are never solely pectoral. The cerebral hemispheres 

 in existing ungulates are well convoluted. {Flower and Lydekker., 

 abridged.") 



Suborder ARTIODACTVLA. 

 ARTIODACTYLES. 



Premolar and molar teeth usually not alike, the former being 

 single and the latter two-lobed. Last lower molar of both first and 

 second dentition almost invariably three-lobed: and the first tooth 

 of the upper cheek series alwaj's Avithout a milk-predecessor. Nasal 

 bones not expanded posteriorly. Dorsal and lumbar vertebrae to- 

 gether always nineteen, though the former may vary from twelve to 

 fifteen. Third and fourth digits of both feet almost equally de- 

 veloped. Stomach almost always more or less complex. Colon con- 

 voluted. Caecum small. Mamma> fcAv and inguinal, or numerous 

 and abdominal. {Flower and Lydekkev, abridged.) 



Section SXJINA. 

 PIG-LIKE ARTIODACTYLES. 



The existing members of this group are characterized by their l)un- 

 odpnt molars and the absence of a complete fusion of the third and 

 fourth metapodials to form a " common bone."' The full Eutherian 

 dentition is very frequently present. 



The existing swine-like animals may be divided naturally into 

 three families: I. Hippofotamidw ; 11. Suidce^ or true pigs; III. 

 Dieotylid oe ,f or peccaries. {Flower and Lydekker.) 



a The skeleton of u fossil elephant existed in the Papago well, Pozo Vevde, 

 Sonera, jNIexico. I ohtained fi-agnients of 1)one and one molar tooth, which 

 were sent to the U. S. National ;\Iuseum in 1893, and identified by J. M. Gidley 

 as Elephas colomhl Falcon. 



