278 DE. W. a. KIDEWOOD ON THE 



backwards at the hind end of the cranium, beneath the parietal 

 a.nd above and external to the epiotic, is a shallow depression 

 hardly worthy of the name of fossa, although the position of the 

 -depression is that of the posterior temporal fossa. There is no 

 subtemporal fossa. 



The parasphenoid is flat and broad, but becomes narrower 

 immediately beneath the orbits. It possesses no lateral peg for 

 articulation with the hyopalatine arch, and bears no teeth. 

 There are no posterior wings to the parasphenoid, and the eye- 

 muscle canal does not open behind. The vomer is an edentulous 

 thin plate of bone, square in shape and tilted up in front, and 

 movably hinged to the front of the parasphenoid. The most 

 obvious part of the mesethmoid is a bar of bone with a concave 

 anterior edge, set transversely across the anterior ends of the 

 frontal bones. In addition to this, however, is a stout endosteal 

 part which can be seen from the front of the skull only, and 

 which extends downward to the posterior end of the vomer. 



The hyopalatine arch articulates with the cranium by a single 

 head, and articulates with the prefrontal just lateral of the 

 junction of the vomer with the parasphenoid. The palatine 

 extends as a thin rod of bone some distance in advance of this. 

 The post-temporal is nearly triangular in shape, but with a notch 

 in front which separates the epiotic limb from the supratemporal 

 limb. There is no opisthotic limb. The nasal bones are not 

 recognisable. Around the eye are five bones — two small rect- 

 angular supraorbitals, one postorbital of moderate size, one 

 suborbital, considerably larger, and in advance of it and of about 

 the same size is another suborbital which nearly touches its 

 fellow of the opposite side below the extreme front part of the 

 head. 



The opercular bone articulates in the usual manner with a 

 posterior head of the hyomandibular, and below it is a sub- 

 opercular of about one-sixth its size. The number of branchio- 

 stegal rays is three. The preopercular is small, barely larger 

 than the subopercular, but its relations are perfectly normal : 

 e. g., it receives the sensory canal from the squamosal, it is 

 attached by fibrous tissue to the outer surface of the hyoman- 

 dibular, and its posterior edge overlaps the front of the opercular 

 bone. The greater part of the preopercular is concealed by the 

 postorbital bone. 



