438 BKITTSU FOSSIL REPTILES. 



pressed by a very shallow and wide, longitudinal or vertical channel ; but this is 

 scarcely marked in a second specimen of a muzzle of the same species. In both 

 specimens the outer surftxce of the flattened part is less smooth than at the sides 

 of the muzzle, being impressed by numerous irregular, linear grooves, seemingly 

 vascular, affecting the vertical direction at the upper part, and the transverse 

 direction at the rest of the surface. 



The ridge where the two sides of the muzzle meet, above and beyond the 

 flattened surface, is more obtuse and is relatively thicker than in Pterodacti/lus 

 Sedgwickii. Were the same curve to be continued from the part of the ridge 

 preserved until it became horizontal, the vertical diameter of the skull at this part 

 would be not less than three inches ; it may, however, have arisen to a greater 

 height, for the contour is not regularly curved, but subangular, as shown in figs. 1 

 and 2, PI. 11. 



The facial part of the skull must have been narrow in proportion to its height, 

 and, no doubt, also to its length. Tlie broadest pare of the present fragment does 

 not exceed one inch and a quarter at the fourth pair of sockets ; the adherent 

 matrix {m,m, figs. 4 and 5) gives a seeming greater breadth to this part of the skull. 



The sockets of the first pair of teeth («) are three lines apart, the interspace 

 equalling the largest diameter of the socket ; the bone forming this anterior 

 termination of the palate projects as a convexity below the level of the alveolar 

 openings, the plane of which is a little inclined outwards. This inclination is 

 increased in those of the second pair of sockets, which are nearly double the size 

 of the first, and are five lines apart. The second is separated from the first socket 

 by an interval of two lines ; its outlet has a full, oval form. The third socket is 

 four lines distant from the second, and exhibits the same ratio of increase of size; 

 there is a sliallow, vertical depression on the outer alveolar wall, between the second 

 and third tooth, the socket of the latter appearing to have made a slight pro- 

 minence on that part of the jaw. The palate at the interspace between the second 

 and third pairs of sockets is flat, showing no trace of the median ridge charac- 

 terising that part of the upper jaw, or of the groove at the corresponding part of 

 the lower jaw, in the Pterodacf^Ius Sedgwickii. 



The upper jaw of the Pterodactylus siii/us, in the present specimen, has been 

 partially fractured across the third pair of sockets (figs. 1 2, 5, «), of which only 

 the fore part of the left one is here preserved, showing well-marked vascular 

 grooves. Its outlet, from this fracture, appear to be of a larger oval or ellipse than 

 in the second socket. 



The fourth socket {</) is preserved only on the right side, with about the right 

 half of the corresponding part of the bony palate. The outlet of this socket 

 resembles in shape and size that of the second; it is three lines distant from the 

 third socket. 



