48 
FOSSIL REPTILIA OF THE 
present specimen, conform to the pterosaurian characteristics of these vertebrae, as shown 
in those of Pterodactylm Sedytoiclcii, described and figured in the ‘ Monograph on the 
Fossil Reptilia of the Cretaceous Formations,’ Supplement No. 1 (1859), pp. 7 — 10, 
PI. II, figs. 7 — 18 ; and in those of Pterodacfylus simus, ib. Supplement No. Ill (1861), 
p. 7, PI. II, figs. 1 — 5. 
The skull preserved in the present specimen agrees in size with that in the slab pre- 
viously received (PI. XVII), repeats the characteristics of the genus Bimorjjhodon, and shows no 
differences of greater degree or value than may be set down to individual modifications. The 
part defective and partly obscured by intrusive bones from other parts of the skeleton is un- 
fortunately that which leaves the precise determination of structure unsatisfactory in the pre- 
viously described specimen. A trace only of tympanic remains at 28, and of the descending 
styloid process of the mastoid at 8 : the thick metacarpal of the wing-finger (iv, ?«), intrudes 
into the orbit, and overlaps the upper end of the malar (26). More of the part of the frontal 
forming the superorbital arch (ii) is shown than in PI. XVII. Part of the concave surface 
of the orbital cavity beneath the superciliary ridge is here seen. The lacrymal ( 23 ) or 
descending branch of the prefrontal ( 14 ) meets the ascending process from the combined 
malar and maxillary, dividing the orbital from the antorbital cavity. The true size and 
shape of the latter vacuity ( 0 ) is here well displayed. The maxillary styloid process ( 2 P) 
rises, at the same angle backward as in PI. XVII, to join the nasal ( 15 ). The medial branch 
or ray of the premaxillary (22'), the end of which is depressed below the prefrontal in 
PI. XVII, preserves its position in the present specimen, and yields the true arched 
contour of the profile of this remarkable skull. 
The entire vertical extent of the vast narial vacuity, n, is here given, the longitudinal 
one, inches, precisely agreeing with that in the first-described skull. The anterior 
part of the premaxillary (22) shows, also, the same proportions and shape, viewed side- 
ways, as in the first specimen. The conformity is instructively continued in the characters 
of the dental system. The apex of the crown of the laniary (PI. XVIII, 1 ) from the fore end 
of the premaxillary shows the same curvature and proportions as in PI. XVII ; the same 
interval divides it from the second laniary ( 2 ) ; the longer interval, again, occurs between 
the second and the third laniary, with a longer and less curved crown. After an interval 
of seven lines comes the fourth tooth ( 4 ), corresponding in size and shape with the one 
which is displaced in PI. XVII, 4 '. After an interval of nine lines the apex of the crown ofi 
seemingly, the successor of the fifth laniary ( 5 ) appears. It may be, normally, smaller 
than the rest; the socket of this tooth is feebly indicated in the subject of PI. XVII. The 
sixth laniary (6) shows the same size and relative })osition as in that subject, and the same 
may be said of the five succeeding teeth, save that the last is rather larger than in PI. XVII, 
which also shows an additional small hind cuspidate tooth. The suture between the 
premaxillary ( 22 ") and the maxillary ( 21 ) is more plainly discernible in the present specimen. 
The extent of alveolar surface of the left upper jaw occupied by the above- described 
dental series is 5 inches 3 lines. 
