234 DR. MORTON'S OBSERVATIONS ON 



Inches. 

 Vertical diameter of the orbit, - - - - - - --2. 



Horizontal diameter of the orbit, - - - - - - - -1.8 



Vertical diameter of the occiput, measured from the lower margin of the foramen magnum - 3.6 



Lateral diameter of the foramen magnum, ------- 1-3 



Vertical diameter of foramen magnum, - - - - - - -1.1 



From the centre of the orbit to the lateral margin of the occiput on the same plane, - - 5.1 



From the centre of the orbit to the anterior end of the upper maxilla, _ - - 7.3 



Length of the lower jaw, ____----- 10.2 



From the angle of the lower jaw to the top of the coronoid process, _ - _ - 5.6 



Depth of the lower jaw from the alveolar margin of the fourth false molar to the base, - 2.2 



Length of the symphysis, measured externally, ___--- 3.3 



Distance between the outer margins of the angles of the lower jaw, - - - - 8.9 



Distance between the outer alveolar margins of the canines of the lower jaw, - - - 4.5 



The preceding remarks and measurements, and the annexed drawings, almost 

 preclude the necessity of further specifications on the cranial structure of this animal. 

 It may be observed, however, that in the H. Liheriensis there is a slight but uniform 

 convexity of the upper surface of the skull from orbit to orbit, and between the 

 occipital and nasal bones ; while, on the contrary, in the H. amphibius the orbits are 

 remarkably elevated, and the intermediate surface is concave. 



In my first description I committed an error in describing the orbit as nearly 

 intermediate between the two extremes of the head. This mistake is corrected in 

 the table of measurements. At the same lime it is to be remarked, that the orbit is 

 placed much nearer a central point than in the H. amphibius, as will be more 

 particularly evident in the reduced vertical view, PI. 34, fig. 5. 



The lachrymal bone in this species is remarkable for its extreme tenuity as well 

 as for its form. It rises with prominent convexity from the floor of the orbit for 

 nearly an inch in length, and is marked by a slight, sub-central, vertical constriction, 

 that gives it a bilobed shape. 



Dr. Goheen, (who from the first of his seeing these bones, considered them 

 indicative of a new species,) has obligingly favoured me with the following 

 memorandum. " These animals abound in the river St. Pauls, and vary 

 in weight from four hundred to seven hundred pounds.* They are slow and 

 heavy in their motions, yet will sometimes stray two or three miles from the river, in 

 which situation they are killed by the natives. They are extremely tenacious of life, 

 and almost invulnerable excepting when shot or otherwise wounded in the heart. 

 When injured they become irritable and dangerous, but are said by the natives 

 never to attack them when in their canoes. The negroes are very fond of the flesh, 

 which seems to be intermediate in flavor between beef and veal." 



* .Judging from the osteology of the animal, it can rarely attain this maximum weight. 



