2 FOSSIL REPTILIA OF THE 



of the Tertiary and modern times. 1 The resemblance was carried out by the unequal size of 

 the teeth in the same jaw, as shown by portions of maxillce and mandibula subsequently 

 acquired. But the Wealden teeth differed in the longitudinal ridges of enamel 

 traversing the exterior of the crown ; such ridges being numerous, close-set, and neatly 

 defined. Two of the ridges, longer than the rest, traverse opposite sides of the tooth, 

 about midway between the fore and hind outlines in the side-view. In the larger teeth 

 (PI. I, fig. 3) they extend from the base to the apex ; in the smaller teeth (ib., 

 figs. 4 and 6) these opposite ridges are limited to the apical half of the crown, to which 

 they may give somewhat of a trenchant character. At the back part of the series 

 (ib., fig. 7) the dental crown becomes obtuse, as it is shown to do in a former Mono- 

 graph (torn, cit.), in Alligator HastingsicB and Crocodilus Spenceri. 



On these characters the present genus and species were originally founded, 2 and the 

 fortunate preservation of two teeth in the lower jaw of the dislocated parts of the 

 skeleton from the Purbeck stone determined its generic, if not specific, affinity with 

 the Wealden type of Goniophulis crassidens. 



In the notable slab from Swanage the parts which first and more especially attract 

 attention are the numerous, large, bony, dermal plates or scutes. These are scattered 

 irregularly over the slab, and in their number and relative size bring the species much 

 nearer to the extinct Teleosaurs than to any of the existing Crocodiles ; they differ, 

 however, from both the dorsal and ventral scutes of the Teleosaur in their more regular 

 quadrilateral figure (PI. IV, fig. 1) ; they are longer in proportion to their breadth than 

 most of the Teleosaurian scutes, and are distinguished from those of other Crocodilians, 

 recent and fossil, by the presence of a conical, obtuse process (ib., a ), continued from 

 one of the angles, transversely to the long axis of the scute : it is analogous to the peg or 

 tooth of a tile, and fits into a depression on the under surface of the opposite angle of 

 the adjoining scute ; thus serving to bind together the plates of the imbricated bony 

 armour, and repeating a structure which is characteristic of the large bony and enamelled 

 scales of many extinct Ganoid Fishes. Some of the scutes in the Swanage specimen 

 are 6 inches in length and 2^ inches in breadth ; the average length is that shown in 

 the figure. 



The exterior surface of the scute is impressed by numerous deep, round, oblong, 

 rarely angular pits, from two to four lines in diameter, and with intervals of about 

 two lines, defined by convex, reticularly disposed ridges of the bone ; but a larger 

 proportion of the border of the scute is overlapped by the contiguous scute than in 

 the Teleosaur, and this part (PI. IV, fig. 1, c ) is smooth and thinner than the rest of 

 the scute. The whole of the inner surface of the scute (PI. Ill, 6) is smooth ; but on 



1 See " Monograph on Reptilia of the London Clay," in the volume of the Palseontographical Society, 

 issued for the year 1849. 

 3 ' Report,' loc. cit. 



