Osteology of Loxomma Allmanni. 45 



presphenoidal part ; in front of the fracture the ridge tapers 

 gradually to a point, which is probably the anterior end of 

 the median part of the vomer, and where it is joined by the 

 vomerine palate-plates. 



The teeth are all broken off at about the level of the alveoli, 

 except four on the right side. The whole surface of the palate 

 between the palate-plates of the maxillaries, (namely, the 

 palate-plates of the palate-bones and of the vomers) are covered 

 all over with small, somewhat pointed, and thickly set granu- 

 lations ; the vomerine and premaxillary divisions of the palate 

 are the strongest parts of the upper jaw. There is no anterior 

 palatine foramen. 



The malar or zygomatic arches are open and wide, being 

 about 4 inches long by 2 inches at the widest part, and of 

 an elongated ovoid shape, their apices pointing forwards. 



The posterior nares are placed far back, at the posterior- 

 part of the pterygoids, and close together, but distinct from 

 each other. 



Behind the nares are two bony projections, apparently from 

 the basisphenoid ; this bone is difficult to define, but is at- 

 tached to the apex of the basioccipital behind. This is of a 

 triangular form ; and its forward-pointing apex is wedged in 

 between the converging posterior lateral projections of the 

 cranium, bordered by the ossa quadrata. At its base is seen 

 the cup-shaped cavity for articulation with the body of the 

 atlas. 



Individual hones. — The premaxillaries are well preserved, 

 and are firmly united by the median suture ; their alveolar 

 border or arch is somewhat elevated above their palate-plates, 

 and contains four teeth on each side of the symphysis ; all are 

 broken off on a level with the alveoli. 



In another specimen of Loxomma in Mr. Atthey's posses- 

 sion there are five teeth on the right and six on the left side. 



The last two teeth at the extremities of the premaxillary 

 arch are only half the size of the others, and are placed nearer 

 to each other than the rest are. 



Each dental interspace is fully occupied by a wide and deep 

 depression, which varies in size with the distance at which the 

 teeth are apart. These depressions, it has been said, are des- 

 tined for the reception of the points of the mandibular teeth 

 when the mouth is closed ; as, however, we doubted the cor- 

 rectness of the assertion, Mr. Atthey made transverse sections 

 through these depressed spaces and the adjacent parts of the 

 jaw, taking in some of the teeth ; and then, under a low mag- 

 nifying-power, we discovered in each case, a little below the 

 surface of the depression, the remains of the root of a former 



