449 



of the crowns of both the upper and under teeth fit into the interspaces of those of the oppo- 

 site jaw, when the mouth is closed. The teeth progressively diminish in length, without 

 decrease of basal breadth, as they are placed further back. A portion of the right tympanic 

 bulla has been removed to expose its cavity aud part of the petrosal within. In the length 

 of the mandibular symphysis the Platanista resembles the Physeter : in the broad, converging, 

 maxillary crests it resembles the Hyperoodon : in the expanse of the temporal fossae, the 

 strength of the zygomatic arches, the shortness of the molars and the smallness of the orbits, 

 it is peculiar among the true Cetacea. 



Presented by David WaUich, M.D. 



2432. The upper and lower jaws of the long and slender-jawed Dolphin (Platanista 

 gangeticd). 



The number of alveoli of the teeth in this specimen is : ^--ff Both the upper and lower 

 maxillary bones are much elongated and compressed ; the symphysis of the lower jaw is co- 

 extensive with the long dental series, and the teeth rise so close to it that those of one side 

 touch the others by their bases, except at the posterior part of the jaw ; the lateral teeth are 

 similarly approximated in the upper jaw at their median line of union, which line is compelled, 

 by the alternate position of the teeth, to take a wavy course. In the preceding cranium of a 

 much smaller and perhaps younger animal, the teeth of one side do not touch those of the 

 other side. Contrary to the rule in the Delphinidce, the anterior teeth retain their prehensile 

 structure, while the posterior ones soon have their summits worn down to their broad bases. 

 The implanted base of the tooth is remarkably expanded in the antero-posterior direction, 

 and its outer surface is augmented by longitudinal folds hike those of the teeth of Sauroid 

 fishes, but weaker than in them : sometimes the posterior tooth is implanted by two short 

 fangs, which is a still more exceptional character in the existing carnivorous Cetacea. 



This specimen is the original of the figure given by Sir Everard Home in the ' Philosophical 

 Transactions' for 1818, p. 419, pi. xx. It was presented by Dr. Roxburgh, who first figured 

 the species in the 'Asiatic Researches' for 1781, to Sir Joseph Banks, and was presented by 

 Sir Joseph to the College, through the hands of 



Sir Everard Home, Bart., V.P.E.S. 

 Genus Delphinus. 







2483. The skeleton of a female Bottle-nose Dolphin (Delphinus tursio). 



The number of alveoli in the upper jaw is 23 23=46 ; that of the lower jaw 21 21 =42. 

 Of the 7 cervical vertebrae the first two are anchylosed together ; the other vertebrae are 53 in 

 number. Of these the thirteen anterior ones support moveable ribs : twenty-nine have trans- 

 verse processes without ribs : the thirty-third vertebra from the skull first begins to support 

 a haemal arch ; but in that and the two following vertebrae the haemapophyses are disunited, 

 and are represented by small flattened ossicles. The sk terminal vertebrae consist of the 

 centrums only, and are much depressed. The metapophysis begins to project from the 



3 M 



