14 PEOFESSOE ELOWEE ON EISSO'S DOLPHIN. 



animal of so early an age ; but in other respects it does not differ materally from that of 

 the other specimen. 



The total number of vertebrae is 69, being divided into 7 cervical, 12 dorsal, 20 lumbar, 

 and 30 caudal ; this gives one additional vertebra in the lumbar region, an individual 

 variation by no means uncommon in the Cetacea. 



The bodies of the first and second cervical vertebras are united ; but those of all the 

 others consist of very thin plates still separable from each other, or in some cases, as 

 between the fourth and fifth, united by a partial ankylosis in the centre of the disk. 

 Except in the atlas and axis, the arches have not yet united with the bodies ; but the 

 spines are joined into two sets — one consisting of the first, second, and third, and the 

 other consisting of the last four. The metapophyses of the posterior dorsal and anterior 

 lumbar vertebras are more developed than in the adult specimen, resembling those in 

 Van Beneden and Gervais's figure of the skeleton of G. rissoanus. The chevron bones 

 are twenty-one in number. 



There are twelve pairs of vertebral ribs, of which the first six have necks; in the 

 seventh the neck is represented by an unossified ligament. The sternal ribs resemble 

 those of the adult in number and connexions. The three segments of the sternum are 

 not united by bone ; the last is divided in the middle line into two separate pieces. 



The skull, as is usual with young animals, differs from that of the adult in the large 

 size, globular form, and smooth outlines of the cerebral portion as compared with the 

 rostrum. It much resembles that of a young Globicephalus of corresponding age, but 

 can be at once distinguished by the convexity of the upper surface in front of the narial 

 aperture. The under surface of the anterior portion of the maxilla has a well-marked, 

 but narrow, longitudinal groove near the outer border, corresponding to the alveolar 

 line of other Dolphins ; but there are no distinct alveoli. The opening of the vascular 

 canal at the apex of the praemaxilla is very distinct. In the anterior portion of the 

 upper edge of the mandible is a deep narrow groove, 4J inches long, the anterior 

 portion of which is dilated into a wide alveolar chamber (T8 inch long on the right 

 side and 1*5 inch on the left), divided by very imperfect septa into chambers for lodging 

 the teeth, four on the right and three on the left side. The principal dimensions of the 

 skull are given at p. 10. 



The carpal bones and the phalanges, though of course far less developed, are the 

 same in number as in the adult, except that the minute terminal ossifications of the 

 second and third fingers of the latter were not yet apparent 1 . 



There can be no doubt that these two animals belong to a peculiar group of the 

 Cetacea constituting the genus Gram/pus of Gray, of which two species are commonly 



1 Some notes upon the visceral anatomy and external characters of this individual have been given by 

 Dr. Murie in the ' Journal of Anatomy and Physiology,' Nov. 1870, p. 118. The differences in Dr. Murie's 

 description of the external surface from that given above, are probably due to changes resulting from the 

 greater length of time that had elapsed between the death of the animal and his examination of it. 



