102 PROCEEDINGS OF THE ACADEMY OF [1883. 



are not visible at that point). From this point it is a deep atten- 

 uated keel, dividing the palate into two deep channels, and 

 extends as far posteriorl3'^ as the nares. The posterior part is 

 free beyond its base. The entire vomer is like that seen in various 

 natatorial birds. The anterior maxillopalatine foramen separates 

 the vomer from the maxillaries anteriorly. Posteriori}', the fora- 

 men is bounded by an ascending process of the maxillary bone, 

 which is in contact with the palatines posteriorly. 



The premaxillarg is divided its whole length. At the middle 

 line above, it passes between the nasal laminte, while below it 

 forms the roof of the muzzle part of the mouth, and the floor 

 of the huge nareal fossa on each side of its spine. This part 

 extends posteriorly as a thin lamina, each meeting that of the 

 opposite side on the middle line, and recurving upwards, forming 

 a median superior crest. The horizontal portion extends above 

 the maxillary bone, between it and the descending postnareal part 

 of the nasal, and extends over the anterior part of the lachrymal, 

 intervening between the anterior extremity of the malar, and the 

 posterior extremity of the nasal. Its posteiior portion develops 

 a rib-like projection, which descends downwards and forwards 

 towards the anterior part of the maxillary bone, and disappears. 

 This bone perhaps includes the inaxilloturhinal. 



The preorbital region includes a not unusual arrangement of the 

 elements. The prefrontal bone descends as far as the middle of 

 the anterior border of the orbit, and to the lachrymal. The 

 orbital edge of the latter is interrupted by an element which pre- 

 sents a vertical edge outwards, and appears to be distinct from 

 it, extending under it anteriorly, and separated from it by a ver- 

 tical groove externally. It is, perhaps, the snperciliar}^ bone 

 of Cuvier, which occupies a somewhat similar position in the 

 Varanidee. Below the lachrymal a small part of the orbit is 

 bounded in front by the jugal. The latter sends forward a laminar 

 prolongation over the maxillary, separating it externally from the 

 posterior extension of the niaxilloturbinal. 



The mandibular ramus includes all the elements of the reptilian 

 jaw. The arrangement posteriorly is a mixture of that of the 

 crocodile and that of the lizard, while the remaining portion is 

 peculiar. T!ie angle is formed by about equal parts of the articular 

 and angular, the former furnishing the external half,- the latter the 

 internal. There are a huge dental fossa and foramen, as in the 



