The only species which it resembles is _O. brachyrhinus_, but differs from that in the flatter, narrower palate, which makes a greater angle with the rostral keel, and in the smaller teeth, which are separated by wider interspaces. XIV. Ornithocheirus nasutus (Seeley). Case. Comp. Series. Specimen. =J= _c2_ 11 1 A fragment of a premaxillary bone 6 inches long. It somewhat resembles _O. Cuvieri_ in the aspect of the palate, but the jaw is more elongated, and expands from side to side at the anterior end. The teeth are opposite to each other in front, but become irregular after the sixth. The palate measures behind the second pair of sockets 3/4ths of an inch, behind the third pair it is a sixteenth of an inch wider, behind the ninth pair half an inch, and in the last two inches it begins to widen again. A sharp keel arises behind the second pair of sockets and becomes more prominent to behind the tenth pair, when the channel which accompanies it on each side seems to disappear. The first pair of teeth, which look forward, is smaller than the second and third pairs; they are closer together than those which follow. The third sockets are 7/8ths of an inch from the tip of the snout. Then follow three smaller, more circular teeth, which are separated from each other by interspaces as long as the sockets. The back of the sixth sockets are 2-1/4 inches from the tip of the snout. Then follow two larger more elliptical sockets; after which the sockets become smaller and are separated by longer distances, that between the 10th and 11th pairs is nearly 3/4ths of an inch. The height of the jaw behind the second pair of sockets is 5/8ths of an inch, behind the sixth sockets 15/16ths, behind the tenth sockets 1-1/4 inch. In front, the nose has the aspect of being compressed from above downward, and behind it is compressed from side to side. The sides are flattened and round into a narrow rostral ridge which is depressed at the anterior end. XV. Ornithocheirus polyodon (Seeley), Case. Comp. Tablet. =J= _c_ 21