614 Observations on a rare British Dolphin. 



which looks backwards, and is 1 inch in length and \\ in 

 breadth. 



Anterior Extremities. 



These organs of locomotion are situated very low down 

 towards the under part of the thorax ; and are — 



FT. IN. 



Distant from the extremity of the muzzle 1 9 



Length of the anterior fin 1 4 



Breadth of the carpus „ 6 



Circumference of ditto 1 1 



Dorsal Fin. 



This organ rises about the middle of the back, but rather 

 nearer to the tail than the snout ; it is of a triangular form, 

 inclined backwards, convex along its anterior and concave at 

 the posterior border. The anterior root emerges, by a thick 

 fold of the common integument, at the distance of 3 feet 10 

 inches from the extremity of the muzzle, whilst its posterior 

 root is inserted at 3 feet 6 inches from the extreme expansion 

 of the tail. A prominent ridge extends from the posterior 

 root to the distance of 8 inches, where it gradually becomes 

 lost, but rises again into a well-defined raphe at about 18 in. 

 from the termination of the vertebral column. Its surface is 

 partially notched, and it serves to separate the caudal lobes. 



FT. IN. 



Length of the dorsal fin along its anterior border 1 5 



Ditto ditto along its posterior margin 1 



Expansion of the base of this organ 1 4 



Tail. 



The caudal fin is composed of two distinct lateral lobes ; 

 each arises by a distinct root: when viewed conjointly they 

 describe a crescent, the concavity of which is turned back- 

 wards. The extreme lateral expansion of the lobes is 22 

 inches, and each lobe measures from the raphe to its extremi- 

 ty, 1 foot. 



Character of the Teeth. — Having already announced 

 that each side of both jaws contains twenty-one teeth, it re- 

 mains for me to make a few observations on the general cha- 

 racter of these prehensile instruments, as one of the most im- 

 portant specific characters is obtained from their form and 

 di position. 



The five posterior molars of both jaws are conical recurved 

 spines, the convex surfaces of which look outwards: they ter- 

 minate in sharp points, which have been but partially blunted. 

 The remaining sixteen are conical stumps, the apices of which 



