456 



and in the less development of the median vertical ridge. The contour of the occiput at this 

 part is straight : it presents a double sigmoid curve in the Great Grampus (Delphinus area) . 

 The slender nasal processes of the premaxillaries form convex ridges in this skull : they are 

 more flattened in the Great Grampus. There are two small additional teeth at the back of the 

 series, which may depend upon the present specimen having belonged to a younger individual. 

 The slight differences noticeable in the skull chiefly depend upon muscular attachment, and 

 are of a kind to characterize varieties, not to establish specific distinctions. 



Purchased. 



2518. The skull of the Black Grampus (Delphinus melas). 



Number of alveoli: |^^=46. The teeth are moderately small, conical, subincurved, 

 decreasing to the two extremes of the series. The fourth to the tenth inclusive are subequal. 

 The symphysis of the lower jaw is subtriangular, and curves from below upwards at its ex- 

 tremity. 



Hunterian. 



2519. The skull of the Round-headed Grampus (Delphinus globiceps}. 



Number of alveoli : ^=30. 



o a 



This skull corresponds closely with that of the Delphinus globiceps of Cuvier, figured in 

 the 'Ossemens Fossiles,' torn. v. part i. pi. 21. figs. 11-13. It differs in the closer proxi- 

 mity of the occipital condyles to each other below, and the end of the flattened upper jaw is 

 rather more obtusely rounded. 



Presented by Fred. D. Bennett, Esq., F.L.S. 



2520. The skull, wanting the lower jaw, of the Round-headed Grampus (Delphinus 

 globiceps). 



Number of alveoli: 10 10. The upper jaw is less obtusely rounded than in the pre- 

 ceding specimen : the teeth are relatively smaller, and more pointed. The outer margin of the 

 superorbital arch is flatter, and joins the upper surface at a right angle, being separated from 

 it by a ridge : in the preceding specimen the outer margin of the orbit is convex, and passes 

 by a gradual curve into the upper surface. The whole of the upper surface of the beak being 

 formed by the premaxillaries, in the present specimen, the maxillaries slope down more gra- 

 dually, and therefore appear in the upper view of the skull. 



Presented by Lieut. Colquhoun. 

 Genus Monodon. 



2521. The skeleton of a female Narwhal (Monodon monoceros}. 



Beside the 7 cervicals, which are here unanchylosed, there are 56 vertebrae, twelve of which 

 support moveable ribs, and six of these join the sternum. The twenty-seventh vertebra begins 

 to have hsemapophyses attached to its centrum. 



Mus. Brookes. 



