SIR E. OWEN OX A TRIASSIC SAUEIAX. 



3 



less than iu the toothless Triassic species quoted. Their proportions 

 and periphery are more nearly repeated by the Crocodiles, among 

 recent forms, than by any known species of Lizard or Chelonian. 

 The pterygoids (fig. 3. 2-1) divide, with the presphenoid, these vacu- 

 ities from each other; the diverging fore ends of the pterygoids join 

 the palatal and palato-niaxiliary boundaries of the posterior nostrils 

 (palato-nares). As in the Triassic Dicynodonts and later Crocodilia, 

 the palate is toothless. 



The mandible is deep and strong ; the rami coalesce at the sym- 

 physis ; but the sutures between the constituents of the rami are 

 retained, those, for example, between the dentary (32), the angular 

 (30), and surangular (29) (figs. 1 & 3). 



The angle of the jaw is not produced, as in the Crocodile, beyond 

 the articular element ; in general shape and bony strength the man- 

 dible of Galesaurus resembles that of a Mammal. 



The dentition of the present specimen is in a state of preservation 

 so much better than in the type Gralesaur, as to call for the present 

 description and illustrations. 



The series of upper molars of that fossil (pp. cit. pi. xviii. fig. 7) 

 were restored as to number in pi. xviii. from remains of the inner 

 enamel-coating of parts of the crown and of the fangs of teeth of 

 the upper jaw. The opposing molars of the lower jaw afibrdea 

 further indications of molars, and better ones of the canines and 

 incisors. The laniariform character of the canines, their number, 

 position, and relative size, clearly indicate the resemblance of these 

 teeth to their homologues in the carnivorous Mammalia. 



In the subject of the present paper the entire crown is preserved 

 in four of the upper molars ; the enamelled portion, or crust, shows 

 less length and greater breadth than appears in the above-cited 

 restoration (1876), in which part of the preserved fang is included 

 in the restored outline of the crown. In the perfect molars of the 

 present specimen (fig. 1) the crown shows less length and greater 

 breadth than in the previous restoration ; it is moderately convex 

 externally, triangular, with the base flanked by a short cusp before 

 and behind; the corresponding margins of the crown are finely 

 crenulate, as in the molars of Cynodraco (op. cit. pi. xvii. fig. 6) and 

 Lycosav.rus (pi. xv. fig. 5, op. cit.) An enlarged outline of a perfect 

 upper molar is now given in PI. I. fig. 4. The incisors with longish, 

 slender, simple-pointed crowns are eight in number in both upper 

 and lower jaws, four in each premaxillary opposed or partially 

 interlocking with 1 the same number in each mandibular ramus ; 

 they show a* slight increase of size from the first to the fourth. 

 The canines (fig. 1, c, c'), one on each side of both upper and 

 lower jaws, have the same laniariform shape and size of crown 

 as in the original fossil of Galesaurus (Joe. cit. pi. xviii. fig. 7, c), 

 A corresponding interspace for reception of the crowns, the mouth 

 being shut, breaks the dental series. In the right maxillary bone 

 the long, deeply implanted root is exposed ; the corresponding part 

 of the lower canine is similarly exposed in the left mandibular 

 ramus. The sum of these characters is shown in the side of the 



b2 



