214 VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 



stylohyal ligament posteriorly. The occipital face is divided by a prominent median 

 keel which is the continuation of a prominent process of the inion. This keel is 

 much stronger than in M. jeffersonii, and in that species it descends upward and 

 disappears in the inion. In this skull it grows more prominent upward, terminating 

 in the process mentioned, which is wanting from M. jeffersonii. The band of 

 ligamentous insertion bordering the inion is narrower than in M. jeffersonii. These 

 characters confirm the specific diversity of M. wheatleyi, the more as those of the 

 occiput are those of maturity, while the individual is considerably smaller. A part 

 of an inion of a second skull in the Port Kennedy collection, which has no teeth 

 accompanying it, resembles more nearly that of M. jeffersonii, though agreeing in 

 size with the skull referred to M. wheatleyi. 



Another portion of the latter skull which may be compared with a corresponding 

 part of M. jeffersonii 'is the lower jaw, of which both rami are preserved, while the 

 symphysis is wanting. Besides the inferior dimensions, the jaw differs from that 

 of M. jeffersonii in the form of the angle. As in that species it is very large, and 

 is produced as far posteriorly as the line which descends vertically from the con- 

 dyle. Its inferior border is convex downward, and then turns upward to an acute 

 upwardly directed apex. The superior border of the angle is concave, and it con- 

 tinues into the border of ascending ramus to the condyle. The coronoid process 

 is large, i. <?., both wide and high, and it has an obtuse recurved apex. This ramus, 

 as compared with that of M. jeffersonii, differs in the concavity of the superior border 

 of the angle, which is straight or nearly so in the latter species, and in its less posterior 

 production, since it extends posterior to the line of the condyle in M. jeffersonii. 

 The inferior border of the ramus is more concave in M. wheatleyi. It is possible 

 that these differences come within the range of specific variation, and it is not possi- 

 ble to determine their value finally, since there is available for comparison but one 

 jaw of each. I suspect, however, that the difference in the forms of -the angles is 

 of some significance. 



No malar bone of a species of Megalonyx has been hitherto observed. The 

 specimen No. 4 exhibits that of one side nearly perfect, and that of the other side 

 lacking only the descending process. In No. 1 the malar of the right side lacking 

 the descending process is preserved. The vertical diameter of this element is much 

 greater than the longitudinal. The portion immediately posterior to the orbit is 

 subquadrate in form. Its posterior border is concave to receive the extremity of the 

 deep and compressed zygomatic process of the squamosal bone, which joins it 

 opposite the middle of the orbit. The anterior border of the malar is abruptly 

 turned posteriorly and there rises above the zygomatic suture a narrow, elevated 

 postorbital process, nearly to the superior plane of the skull. The anterior part 

 of the malar sends downward and backward a long falciform process to below the 

 line of the middle of the mandibular ramus. This process has a convex anterior 

 border. The posterior border is at first straight, and then it becomes concave, form- 

 ing with the anterior border an acute apex. An angular ridge rises from the 

 anterior border and extends along the middle of the external side of the process to 



