254 



The fore part of the tympano-mastoid ridge (Plate XXXVI. fig. 1, 8,12) appears to 

 form the smooth flat hind wall of the articular surface for the mandibular condyle, unless 

 the squamosal should abut against the mastoid beneath the petrotympanic : the cranial 

 bones of this part are evidently modified by original antero-posterior compression. This 

 postglenoid process or wall is 1\ inches transversely, and probably was of great vertical 

 extent when entire ; it is directed from within outward and rather forward. The articular 

 surface lias the same direction, and consists of a hind groove (Plate XXXVII. fig. 3, g) 

 and a front bar, i. e. it is divided from before backward into a strong convexity and 

 a deep concavity ; both are slighly concave transversely ; in that direction the extent 

 of the surface is 3-g- inches ; from before backwards it measures 1^ inch. The malar (26) 

 descends to bound the outer part of the articular bar, to which it contributes a share of 

 the articular surface. The outer end of the groove opens freely upon the base of the 

 zygoma, which it slightly indents ; the inner end is blocked by the descending part of 

 the rugged petrosal. 



The palatal part of the premaxillaries (Plate XXXVII. fig. 3, 22*) is feebly concave, 1 inch 

 5 lines across at the interval between the sockets of i 2 and i 3, then contracting to a 

 breadth of 1 inch at the middle of the diastema (ib. d) between the incisors and molars : 

 the length of this toothless tract is 2 inches 9 lines in a straight line. It is formed by 

 a well-defined ridge gently curved inward until near the socket of the anterior molar, 

 which part of the alveolar tract bends abruptly downward, 9 or 10 lines, below the ridge 

 (Plate XXXVI. fig. 1, 21, d 3). The palate is deep transversely between the right and left 

 anterior molars (Plate XXXVII. fig. 3, d 3, 2i»), their interval in a straight line being 1 inch 

 10 lines. As the palate expands its transverse concavity decreases ; its greatest breadth 

 between the penultimate molars (m 2) is 2 inches 9 lines. Lengthwise the intermolar part 

 of the bony palate (ib. 20*, 21*) is, anteriorly, gently concave, then convex, and again con- 

 cave ; it extends about an inch beyond the last molars, is bounded behind by a thick 

 low rough ridge, a median forward continuation of which divides the back part of the 

 bony palate into two shallow rough depressions or channels leading outwards to behind 

 the last alveoli. The bony palate appears to be entire ; its length from the interspace 

 of the alveoli of the front incisors (aa») is 11 inches 6 lines, from between the alveoli of 

 the front molars to the hind border it is 7 inches 6 lines. 



The huge and extraordinary zygomatic arches (Plates XXXVI. & XXXVII. 27, 26, 21) 

 extend straight forward in parallel lines for more than half the length of the entire 

 skull (Plate XXXVII. figs. 2 & 3), then bend abruptly downward and arch transversely 

 inward to abut against the middle third of the alveolar plates of the maxillaries, a thick 

 transversely extended process (Plate XXXVI. figs. 1 & 2, 21') being continued downward 

 from the angle of the inward curvature. From the hinder origin or " pier" (27) each arch 

 gains, as it advances, a vertical extent of 4 inches 3 lines ; then contracts to one of 3 inches, 

 again expanding slightly in the vertical direction, and greatly in the transverse one, 

 before the inward twist to form the maxillary pier or abutment. The inner surface of 

 the arch is smooth and slightly concave ; the outer surface is rough, convex, and outswells 



