2 FOSSIL REPTILIA OF THE 



by the same character resembled Petrosuchus, but the differential characters were such 

 as could not have been obliterated by growth or age. 



A third form of Crocodilian made a nearer approach in one of the species 



(PI. I, fig. 2) to the average size of the broad-faced genera. A fourth (ib., fig. 1) 



corresponded in size with the subject of fig. 2, but offered no character by which 



it could be legitimately removed from the genus Goniopholis. I commence with the 

 description of this small but well-marked species. 



G'e/22<rs— Goniopholis, Owen} 

 Species — Goniopholis tenuidens. Plate I, fig. 1. 



The dental character of the Araphicoelian genus Goniopholis consists of the numerous 

 close-set, fine, longitudinal ridges of the enamel, two of which, larger and sharper than 

 the rest, traverse opposite sides of the tooth from the base to the apex of the crown, 

 midway between the convex and concave lines of the curvature of the tooth, that is, at 

 the fore and back parts of the crown." 



The general shape and proportions of the tooth-crowns indicate distinctions of species 

 of Goniopholis. The type of the genus is characterised by the thickness and subcircular 

 section of the crown, and the obtuseness of that in the posterior teeth.^ 



In Goniopholis simus^ the proportion of breadth to length of crown is less than in 

 G. crassidens, and this difference is more marked in the specimen from the Feather- 

 bed of Purbeck which forms the subject of fig. 1, PI. I. 



This specimen consists of the chief part of the dentary and co-articulated splenial 

 elements of both rami of the same mandible, partially dislocated at the symphysis. The 

 alveolar tract includes the incisive {{) and molary {m) convexities, without an intervening 

 laniary rising. The incisive convexity includes five sockets, a tooth being retained in the 

 first, third, and fourth on the right, and in the first and third sockets on the left dentary. 

 The foremost tooth has a crown of 6 mm. length and barely 2 mm. of basal breath; each 

 has partially emerged from a socket larger than itself, and exhibits a portion of a tooth 

 in succession to one which has been lost or shed. The socket is separated by an interval of 

 2 mm. from the second. This shows a subcircular aperture of 5 mm. in diameter. The 

 third socket opens at 2 mm. distance from the second. The tooth {h) in the right dentary 

 shows the inner, longitudinally concave side of the crown, with a basal breadth of 6 mm. 



1 'Reports of the British Association,' 8vo., 1841, "On British Fossil Reptiles," part ii, 1841, 

 p. 690. 



2 Loc. cit., pp. 69, 70. 



^ 'Supplement (No. viii) to the Monograph on the Fossil Reptilia of the Wealden and Purbeck 

 Formations,' Palseontographical Volume for the year 18/8, p. 1, pi. i, fig. 7. 

 * Ib. lb., p. 7, pi. V. 



