222 DR. EMBLETON AtfD JIB. ATTHEY Ott TfiE 



forward, expands anteriorly, and appears upon the bony palate" 

 (Owen, " Anat. of Vertebr.," Vol. I., pp. 138 and 146), though 

 it has no teeth. 



By the teeth being anchylosed to the bottom of their alveolus, 

 the base of the tooth blending gradually into the bony structure 

 around. This, however, is a reptilian as well as a piscine cha- 

 racter. The same may be said of the inequality in height of the 

 outer and inner alveolar borders of the mandible and, to a less 

 degree, of the maxilla also. In Loxomma the inner border of 

 the mandibular alveolus is very deficient, leaving the teeth as it 

 were agglutinated to and supported by the external border only, 

 which stands well up. This character exists in many Fishes ; 

 and in Owen's "Anatomy of Vertebrates," Vol. I., p. 888, we 

 find, moreover, the following passage bearing on this character, 

 and showing that it is found also in the Batrachia and the Lacer- 

 tilia : — " In the Scincoids, the Safeguards (Tejus), in most Igua- 

 nians, in the Chameleons, and many Lacertian Reptiles the tooth 

 is anchylosed by an oblique surface extending from the base 

 more or less upon the outer side of the crown to an external 

 alveolar plate of bone, the inner alveolar plate not being deve- 

 loped; in the frogs the teeth are similarly but less firmly at- 

 tached to an external parapet of bone. 



In structure the teeth are labyrinthodont. 



On the other hand the skull of Loxomma, by its form and size, 

 its strength and solidity of ossification, its peculiarly reticulated 

 surface, and by the massiveness of its mandible, resembles much 

 more the skull of the Crocodilia, and especially of the Alligator, 

 than that of Batrachia or Fishes. The presence of limbs as pad- 

 dles allies it with the orders of higher grade than Fishes. 



The nasal bones are a pair; the nasal apertures being both 

 anterior and pharyngeal show that Loxomma was an air-breather 

 like the Crocodiles ; and the existence of such ribs as that figured 

 in Plate IV., fig. 1, confirms this view. 



There is no anterior palatine foramen, neither are there poste- 

 rior palatine or pterygo-maxillary vacuities as in the Crocodile 

 and Alligator. 



The doubtful perforation of the upper jaw in Loxomma is 



