THE TAPIEID^. 311 



fifth digit of the pes appears to be represented by an osseous 

 rudiment. 



In the presence of the full complement of incisors and 

 canines the Tapir is more Horse-like than Rhinocerotic, but is 

 still very peculiar ; for the outer upper incisors are larger than 

 the canines, while the outer lower incisors are much smaller 

 than the canines, and are apt to fall out at a certain age. The 

 canines, are still more closely approximated to the incisors 

 than in the Horse, especially in the lower jaw, and, conse- 

 quently, the diastema is verj' large. The six posterior molars 

 in the upper jaw, and the five posterior molars in the lower, 

 present nearly the same structure. There is a low outer wall 

 with two slightly-marked concavities (in the maxillary teeth) 

 or convexities (in the mandibular teeth) on its outer face. 

 From this two ridge-like laminae run inward and a little back- 

 ward across the crown of the tooth. The valleys are broad 

 and shallow, and the coat of cement very thin. The molar 

 tooth of the Tapir thus represents the plan of structure com- 

 mon to the Ferissodactyle in its simplest form. Deepen the 

 valleys, increase the curvature of the wall and lamina, give 

 the latter a more directly backward slope ; cause them to de- 

 velop accessory ridges and pillars, and increase the quantity 

 of cement ; and the upper molar of the Tapir will gradually 

 pass through the structure of that of the Rhinoceros to that 

 of the Horse. 



In the anterior upper premolar (or milk-molar?) the an- 

 terior moiety of the crown is incompletely developed. In the 

 anterior lower premolar the anterior basal process, which ex- 

 ists in all the molars, is excessively developed, so that the 

 crown of the tooth assumes the bicrescentic pattern of the 

 Rhinoceros's lower grinder. This probably indicates the man- 

 ner in which the Tapiroid form of inferior molar is converted 

 into the Rhinocerotic, or Equine, form. 



The stomach is simple and oval, the cardiac and pjdorio 

 orifices being closely approximated. The caecum is proportion- 

 ally smaller than in the Horse or Rhinoceros. There is no 

 gall-bladder. The heart is devoid of a septal bone and of a 

 Eustachian valve. There is only a single vena cava antei-ior, 

 and the aorta divides into an anterior and a posterior trunk. 

 There is no third bronchus. No distinct scrotum is present 

 There are vesiculfe seminales and prostatic glands, but no 

 Cowper's glands. The placentation is diffuse. The teats are 

 two, and inguinal. 



There are two or three species of Tapir at present living 



