APPENDIX. 463 



being protected by the membrane bones, ohe parieto- 

 frontals above and the parasphenoid below. 



In the dog it is enormously inflated, and the otic capsules 

 are imbedded in its wall. There are supra- and basi- as 

 well as ex-occipital bones ; the parasphenoid is absent, 

 and its place is taken by the basi- and pre-sphenoids, and 

 the lateral walls contain fresh paired ossifications, the 

 ali-and orbito-sphenoids all cartilage-bones. Thesphen- 

 ethmoid is perhaps represented in part by the ethmoid. 



As a result of the inflation of the brain-case, the squa- 

 mosal, which slopes out from above downward in the 

 frog, and overlies the cartilaginous suspensorium 

 (quadrate cartilage), has become a constituent of the 

 brain-case wall, and slopes in from above downward. 

 Jaw Suspension. 



The point of attachment of the jaw has shifted outward, 

 and the original suspensorial cartilage (the quadrate) 

 has, in the dog, taken on a new function as the incus 

 of the middle ear the squamosal superseding it as the 

 suspensory part. 

 flower Jaw. 



Meckel's cartilage, with one cartilage-bone (mento- 

 Meckelian) and two membrane- bones (dentary and 

 angulo-splenial, on either side, in the frog. A single 

 membrane-bone on either side in the dog. 

 Otic Capsule. 



Position as specified. One centre of ossification in the 

 frog, forming pro-otic ; several fuse together and form 

 periotic of the dog. 



There is no bulla in the frog. 

 Palate. 



In the frog the posterior narcs open into the front of the 

 mouth. In the dog the maxillae and palatines send 

 plates down and in (the palatine plates) to cut off a 

 nasal passage from the rest of the buccal chamber, and 

 carry the posterior nares back to the pharynx, thus 

 cutting the vomer off from the roof of the mouth. 



The pterygoids in the dog are much reduced, and do not 

 reach back to the suspensorium. 



The frog has no lachrymal nor jugal. 



