264 



CETACEA 



from nose to median notch between the flukes of the tail, 62i 

 inches ; from the nose to the anterior edge of the dorsal fin, 29 

 inches ; height of dorsal fin, 4| inches ; length of base of dorsal fin, 

 8 inches ; length of pectoral fin, 9^ inches ; breadth of pectoral fin, 

 3| inches; breadth of tail flukes, 13 inches. The under jaw 

 projects about half an inch beyond the upper one. The aperture 

 of the mouth is tolerably wide, and is bounded by stiff immobile 

 lips, and curves slightly upwards at the hinder end. The eye is 

 small, and the external ear represented by a minute aperture in the 

 skin, scarcely larger than would be made by the puncture of a pin, 

 situated about 2 inches behind the eye. The pectoral fins are of 



FIG. 93. The Common Porpoise (Phocfena communis). 



moderate size, and slightly falcate. The upper parts are dark gray, 

 or nearly black, according to the light in which they are viewed, 

 and the state of moisture or otherwise of the skin ; the under parts 

 are pure white. The line of demarcation between these colours is 

 not distinct (washes or splashes of gray encroaching upon the 

 white on the sides), and varies somewhat in different individuals. 

 Usually it passes from the throat (the anterior part of which, with 

 the whole of the under jaw, is dark) above the origin of the 

 pectoral fin, along the middle of the flank, and descends again to 

 the middle line before reaching the tail. Both sides of the pectoral 

 and caudal fins are black. 



The Porpoise is sociable and gregarious in its habits, being usu- 

 ally seen in small herds, and frequenting coasts, bays, and estuaries 

 rather than the open ocean. It is the commonest Cetacean in the 

 seas around the British Isles, and not unfrequently ascends the 



