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 skull of this species, 

 with only a few teetb 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 lias 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 togetlier ; 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 vertebraj 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 8g 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 

 4i inches. 



The processes of the pterygoid bone, which form the bony sheath 

 of the front of the blowhole inside the pterygoid bone, are v?ell deve- 

 loped, 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 pala- 

 tine 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 me that the 

 difference in the form of the pterygoid bones and in the size of the 



