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Show 148 DR. J. E. GRAY ON A NEW DOLPHIN. [Feb. 13, size of the teeth, by the palate being contracted behind, and the form of the pterygoid bones. Mr. Layard sent for examination a full-grown skuli of this species, with only a few teeth in the middle of the tooth-line, and without the lower jaw. He also sent a young animal preserved in salt, which was cut in two parts transversely. The skin has been kept in the British Museum in spirits, and the body has been made into a skeleton. It would appear that the intermaxillary bones become more prominent in the palate as the animal increases in size. In the adult skull they form a distinct part of the palate for about one-fourth of its length. In the skull of the young animal they are scarcely seen, being only visible deep in the suture between the maxillary bones. In the skeleton of the young specimen the index finger is rather longer than the length of the upper and lower arm-bones and carpal bones. The radius and ulna compressed, close together; the ulna about half as wide as the radius. Carpal bones eight; the two upper hinder ones largest; the rest subequal, oblong. Thumb of two very small rudimentary bones, far apart. Index finger of seven, the ring-finger of six, the middle finger of three phalanges; the upper phalanges of the index and middle fingers very small. The cervical vertebrse separate; but they may become united, as the first vertebra is in so young a state as to be formed of four separate bones. The skulls of the adult and young are very much alike; but the beak of the adult skull is much longer, compared with the length of the brain-cavity, than that of the skull of the young animal. In the adult the beak is only rather longer than the brain-cavity, as 8| to 7g. In the young skull the beak is not nearly so long as the length of the brain-cavity, which is 4^ inches long, and the beak only 4^ inches. The processes of the pterygoid bone, which form the bony sheath of the front of the blowhole inside the pterygoid bone, are well developed, and as long as the pterygoid itself, in the young skull only forming a slightly raised ridge on the inner side of the base of the bones. As in some specimens of Lagenorhynchus, there is a triangular space marked on the hinder part of the palate in front of the palatine bones, which is defined by the impression of blood-vessels; this space is very distinct in the young skull, and not so much so in the older one. The inner surface of the intermaxillary bones forms a narrow central prominence in the front of the palate in the older skull; these bones are not seen in the palate, being hidden in the inner edge of the suture of the maxilla in the skulls of younger specimens, showing that the presence or the absence of the sight of these bones in the palate, in some specimens at least, depends upon age. As the three skulls were all obtained from animals inhabiting the seas near the Cape of Good Hope, it has occurred to m e that the difference in the form of the pterygoid bones and in the size of the |