Ornithocheirus microdon (Seeley).
Premaxillary bone. The fossil is nearly 13/4ths inch long, and at the proximal end, where it is less than 3/4ths of an inch high, has flat sides, which converge to form a keel which is depressed anteriorly and rounded so that where fractured in front the bone is 7/16ths of an inch deep. The palatal surface contains two wide concave channels, between which descends a sharp median ridge, which behind becomes more prominent than the alveolar border.
The palate is 5/8ths of an inch wide. The alveolar margins are compressed and rounded. The small tooth-sockets are oval, and four are contained in 11/8th inch; they look downward.
There is a small tip of a jaw associated with this fossil, which is so like that it might be part of the bone broken off before fossilization. It corresponds in every way except that the teeth are closer. In this terminal lanceolate fragment there are in 5/8ths of an inch four teeth. The snout is terminated by two, which are close together.
VII.
Ornithocheirus Huxleyi (Seeley).
The only specimen of this species yet known is the greater part of a dentary bone contained in the Museum of the Geological Survey. An inch and 1/4 long and 3/4ths of an inch wide, it is less than half an inch deep: the sides slowly converge towards the front, and it appears to have had an obtusely lanceolate beak. The under surface is convex, too inflated for trace of a keel, and tapers to the end of the beak, which, with the left alveolar margin is abraded. The palatal surface is smooth at its front end, but two diverging ridges soon arise and form the boundary of a posteriorly deepening mesial channel, which is a quarter of an inch wide at the fracture. These ridges too, which are parallel with the compressed and rounded alveolar margins, convert the lateral spaces into shallow channels. The right side shows the sockets of 3 small oval teeth separated by interspaces wider than teeth. A tooth and two interspaces measure 7/16ths of an inch.
The only cretaceous Pterodactyle which this at all resembles is O. microdon, but the palate is wider than in that species; the sides converge towards each other more rapidly, as though it belonged to a species with a shorter snout.
I am indebted to Prof. Huxley for the opportunity of making a notice of this species.
VIII.