PEOFiiSSOR OWEN ON INDIAN CBTACEA. 41 



of the condyle to the fore end of the symphysis. Each ramus has a convex, almost 

 semicircular posterior margin, curving upward and backward from below (so), where the 

 angle normally exists in other mammals, and then forward to the seat of the coronoid 

 process (29) : at the hindmost part of this curve the border is thickened to form the 

 sessile condyle, adapted to the glenoid surface of the squamosal. Here the border bends 

 outward : as the ramus advances, converging to its fellow, it is slightly bent with the 

 convexity outward, which again is changed to a concavity (lengthwise), where it joins 

 the opposite ramus to form the elongate symphysis (32), which is continued straight 

 forward to its termination. The symphysis here forms rather less than a thifd of the 

 entire length of the mandible, being 2 inches 4 lines in extent. The greatest vertical 

 diameter of the ramus is 2 inches 2 lines ; that at the beginning of the symphysis is 

 8 lines'. In the alveolar groove are partially excavated sockets for nine teeth ; the fom- 

 middle intervals are severally equal to twice the basal diameter of the tooth : at the 

 ends of the series, especially the anterior one, the alveolar intervals are less. The teetli 

 •(PI. XII. fig. 1, and j) are small, straight, conical, obtuse, not exceeding 8 lines in 

 length, of which the cylindrical base has a diameter of 2 lines, that of the crown a 

 diameter of 1| line, with a length of 2^ lines, diminishing to a subrecurved apex. 



The loss of symmetry ia this skull is hardly observable in the general contour, 

 whether viewed from above (PI. XIII. fig. 1) or below (fig. 2) : it is chiefly, almost 

 exclusively, confined to the nostrils and the bones concerned in the composition of those 

 passages ; and this is only conspicuous in the upper surface of the skull. 



In Eui^hysetes breviceps, Bl., according to the figure of the side view of the skuU (copied 

 in PI. XIV. fig. 3), the occipital condyle is more prominent than in JEuphysetes siTmis{?\. 

 XII. fig. 1) : the contour of the superoccipital is concave iu Euphysetes hreviceps, but is 

 convex in Euphysetes simus — very feebly so, indeed, but as far as it departs from a straight 

 line being in the direction of convexity. The most marked difference, however, is the 

 greater proportional length of the rostral part of the, skull — measured, viz., from the ma- 

 lomaxillary fissure (ib. & PI. XIII. k) to the end of the upper jaw (■!2, ^) : in Euphysetes 

 breviceps it forms about two-fifths of the entire length of the skull, in Euphysetes simus 

 about two-sevenths. The proportion of the maxiUary, above the frontal and malar, on 



' " The condyle of the mandible projects from the posterior part of the ascending ramus, which is com- 

 pressed and produced into a low obtuse coronoid process above, and into a similar angle below : a wide 

 excavation, beginning at the inner side of the ascending ramus, deepens and contracts into the dental canal 

 -which enters the substance of the horizontal ramus : a fissure is continued along the inner side of the ramus 

 from this canal, and is the sole indication of a compound structure of the jaw. The vessels and nerves emerge 

 from several foramina at the outer side of the ramus, where it is attached by its long symphysis to its fellow : 

 the upper border of the syraphysial part of the ramus is excavated by a continuous dentigcrous groove, some- 

 what resembling, in the present fatal state, that in the upper jaw. The length of the symphysis in this 

 skull is three-fourths that of the rest of the ramus. In the adult male the disproportionate growth of this 

 part of the jaw leads to more excessive length of the symphysial part beyond the rest of the ramus."— 0,-. 

 cit. p. 444, foetal PJiyseier macrocephalus. 



VOL. VI PART I. ^ 



