STRANDED ON THE BRITISH COASTS. 



159 



(14) Common Dolphin (Delphinus delphis L.). 



About 20 records, one or two of which have been not quite 

 certain, though probable. Three individuals have been recorded 

 from the Northern part of Ireland (Mayo, Donegal) ; two from 

 the North-Eastern coast of Scotland (Inverness, Kincardine); 

 one, somewhat doubtful, from East Anglia (Suffolk) ; and the 

 remainder, either from the English Channel, from Kent to the 

 Scilly Islands, or from the entrance to St. George's Channel, on 

 both sides, from Cork (1918) to Wexford on the Irish side, and 

 on the Welsh coast on the opposite side. None have been 

 recorded in the North Sea area, from Forfar to Norfolk ; and 

 none on the West coast of Scotland; which, however, has 

 provided a curiously small number of records during the whole 

 of these observations. The distribution thus indicated is in 

 agreement with the supposition that this is an oceanic species 

 wdiich is frequently stranded on the more exposed parts of the 

 coast-lines, but comparatively seldom makes its way into the 

 North Sea. The three records from the S. coast of Ireland 

 (including one for 1918) were obtained in February, that from 

 Inverness in April, and the remainder from August to December. 



The Common Dolphin reaches a length of about 7 ft. 6 in. ; 

 and is distinguishable by its very long beak and numerous conical 

 teeth, of relatively small size, with a basal diameter of about 

 in. The teeth are more numerous than in any of the other 

 species here considered, being about 45 in each half of each jaw. 



(15) CommOx\ t Porpoise (Phoccena phocama L.). 



Numerous records, indicating, as generally supposed, that this 

 is the commonest species in British waters. Of those which were 

 certainly determined, the great majority were recorded from the 

 East coast of England, and most of them during the period May 

 to August. Evidence has been obtained in support of tiie belief 

 that the Common Porpoise gives birth to its young in the early 

 summer, and that the length at birth is from 2 ft. to 2 ft. G in. 

 According to Prof. Meek (1918, p. 197), the occurrence of 

 Porpoises near the coast during July and August may be 

 regarded as an inshore migration for parturition and pairing. 



This species differs from all others found on the British coasts 

 in the form of its teeth, which instead of being conical, as in the 

 majority of the species, are broadened at the free end ("spade- 

 shaped"), although the exact form of the broadened part 

 is variable. The teeth undergo a considerable amount of 

 thickening as growth proceeds, and the broadened blade is not 

 infrequently worn away in some of the teeth. About 25, 

 or rather more, are present on each side of each jaw ; though 

 usually two, at the anterior end of the series, remain small and 

 are concealed below the gum. The length of the adult is about 

 5 ft. 6 in. — and this is distinctly the smallest of the British 

 Cetacea. The head is not provided with a beak. 



