﻿22 The Philippine Journal of Science isu 



the frontals (36), and posteriorly with the pterotics (38). On 

 the ventral side there is a fossa for the articulation of the 

 anterior limb of the head of the hyomandibular (10). They 

 are perforated throughout the whole length by the large sensory 

 canals passing from the frontals (36). On the ventral side 

 they articulate internally with the alisphenoids (122). In Plate 

 I the left is seen. In Plate II both are viewed in position, 

 from the dorsal side. In Plate III they are disarticulated, the 

 right having the ventral surface in view, while the left, the 

 dorsal surface. In Plate IV, fig. 2, the right is seen from 

 the right side, as also in Plate VI, fig. 1. In Plate V, fig. 1, both 

 are seen from the ventral side. 



The parasphenoid (66) extends from about the median dorsal 

 portion of the vomer (67) to almost the posterior portion of 

 the basioccipital (69). It sends out lateral lamina? in the region 

 of the probtics (78), and on the sides, in the region ventral 

 to the basioccipital (69), are the posterior openings and grooves 

 from the myodome. Ventrad to the basisphenoid (83) and 

 anteriorly is another thin lamina on each side, which, together 

 with the central "stock" or "rib," help to form the brain cavity. 

 Anteriorly, the articulation is with the vomer (67) and the 

 ethmoid (81), between which this portion lies. In Plate III 

 the parasphenoid is seen from the dorsal side, disarticulated; 

 in Plate IV, fig. 2, in the articulated skull from the right side; 

 in Plate V, fig. 1, in the articulated skull from the ventral; and 

 in Plate VI, fig. 1, in the articulated skull from the right side. 



The vomer (67) anteriorly is broad with 2 triangular patches 

 of teeth. Just back of this "head," there is a horizontal thin 

 portion with a median rib, the latter extending to the posterior 

 end. The dorsal outline is clearly shown in Plate III. It artic- 

 ulates with the ethmoid (81) dorsally, laterally with the pre- 

 frontals (76), and posteriorly with the parasphenoid (66). In 

 Plate II the anterior end of the vomer is seen in the articulated 

 skull ; in Plate III the dorsal side in the disarticulated skull ; 

 in Plate IV, fig. 2, from the right side; in Plate V, fig. 1, in 

 the articulated skull, from the ventral; and in Plate VI, fig. 1, 

 in the articulated skull from the right side. 



The basioccipital (69) forms the centrum of the condyle 

 for the attachment of the atlas (70). There is a longitudinal 

 suture separating it from the exoccipitals (72), and anteriorly 

 a vertical suture separating the basioccipital and exoccipitals 

 (72) from the probtics (78). The longitudinal suture between 

 the basioccipital and exoccipitals (72) passes through the middle 



