Coues.] 92 [June 2, 



sutures, most of the bones, as will be seen, remaining unanchylosed. 

 The epencephalic arch can be detached entire; the basi-, ex-, and par- 

 occipital elements are completely soldered together; but the superoc- 

 cipital shows traces of its original separation, its suture with the 

 exoccipitals displaying the part it takes in the formation of the fora- 

 men magnum (production of the characteristic notch at the upper 

 border). With the arch are brought away the petro-mastoid, tym- 

 panic and large bulla ossea ; but neither of these three are soldered 

 to it; and the two last, moreover, are further separable from the 

 petro-mastoid ; the remarkable quadrate platform of bone surmounting 

 this arch is completely anchylosed with the superoccipital, and seems 

 indeed to form an integral part of that bone, leading to a suspicion 

 that it never formed a distinct interparietal. 1 Just in advance of this 

 questionable plate, moreover, are two distinct little bones, irreg- 

 ularly triangular, together forming a lozenge on the median line; 

 they remain suturely connected with the parietals on removal of the 

 epencephalic vertebra. These may be a bifid interparietal, or ossa 

 wormiana. The parietals are disconnected with each other, and from 

 all surroundings. The squamosals may be removed with some little 

 difficulty; they are free from parietal, frontal, and malar, but begin- 

 ing to anchylose with alisphenoid. The nasals and premaxillaries are 

 very easily removed; a spongy mass is brought away with the former. 

 The lachrymals almost fall out of themselves. The sphenoid may be 

 loosened, but not entirely detached, without violence ; traces of the 

 union of the pterygoids with it remain ; the limits of ali- and basi- 

 sphenoid are plainly seen. The interfrontal suture is plain. The 

 superior maxillaries are distinct from the frontal, and also show the 

 median palatal suture; but the malars and palatines are both com- 

 pletely soldered with them. The large stout palatines, in fact, appear 

 to be the most solid bones of the skull. Besides their extensive and 

 firm union with the maxillaries, their palatal plates fuse together, 

 forming with the corresponding processes of the maxillaries, a strong, 

 bony bridge across the back part of the palate, connecting the molar 

 alveoli. The two halves of the lower jaw remain separable. 



With advancing age nearly all these sutures become obliterated. 

 The most persistent are those between the nasals and their surround- 

 ings, the sphenooccipital, the squamo-malar, and the symphysis 

 menti. These I have never found obliterated, though — particularly 



1 On the other hand, see Owen, Comp. Anat. and Phys. Vert., II, pp. 316, 867. 



