134 FOSSIL MAMMALIA. 



The molars, four in number on each side of the jaws, approxi- 

 mate to each other, are prismatic and squared, and the coronal 

 exhibits two transverse hillocks, separated by a furrow. The 

 bradypi have the molars separated, and preceded by a canine, 

 in the form of a pyramid with three faces. 



The cervical vertebrae appear to have been seven in number, 

 like the unau, and not nine, as in the a'l ; sixteen dorsal ver- 

 tebrae have been collected, and, consequently, sixteen pairs of 

 ribs. There are three lumbar vertebrae, and the caccygian, 

 the knowledge of which is owing to Don Damasio, seem 

 tolerably numerous. The bones of the ilia form a semi-pelvis, 

 rather wide, which indicates that the belly was large. The 

 pubis and the ischion are wanting in the skeleton of Madrid. 



The anterior extremities are longer, but more slender than 

 the posterior, but have not the immeasurable length of those 

 of the ai, nor even of the unau. The femur is thicker than 

 that of any known animal, and its length is only double its 

 greatest thickness ; the tibia and the peroneum, also very thick 

 and short, are cemented at their two extremities ; the shoulder- 

 blade has the same proportions as those of the bradypi ; the 

 existence of the clavicle, and the length of the phalanges of the 

 unguiculated toes, proves that the anterior extremities might 

 have been used for grasping, and even for climbing. The 

 humerus is very wide in its lower part, in consequence of the 

 great development of the crests to which the motores muscles 

 of the toes are attached. The radius, distinct from the cubi- 

 tus, had the power of rotation upon it. On the olecranon was 

 a projection considerably marked. The hand which leant al- 

 together on the ground, had the metacarpus very short, and 

 composed of separate bones. The three middle toes, very thick 

 and long, are terminated by an enormous unguical phalanx, 

 the extremity of which is composed of an arched and conical 

 axis, which sustains a claw, and of a deep sheath, which in- 

 closes the base of this claw, and strengthens it. The two lateral 

 toes are shorter, appear to have had no claw, and were doubt- 



