320 WHALES AND DOLPHINS 



they are small and pointed, with diameter up to x \ t inch. 



The White-sided Dolphin is a North Atlantic species, the 

 range of which extends from Greenland as far south as the 

 British coast and on the western side of the Atlantic south to 

 Cape Cod 



In British waters it is more abundant in the north, in the 

 neighbourhood of Orkney and Shetland, but has been reported 

 as far south as Lincolnshire on the mainland. It has not been 

 known to strand on the west or south coasts of England, and 

 only a solitary record comes from Ireland — from Co. Sligo. 



Oft the Norwegian coast this dolphin is the next commonest 

 species to the most abundantly-occurring Common Porpoise. 



A length of just over 9 feet is attained by adults. 



Schools composed of large numbers of White-sided Dolphins 

 are common ; the species is a gregarious one. In 1926 about 

 thirty stranded at Scalloway, Shetland, part of a much larger 

 school observed off shore on the same day ; again in 1929 thirty- 

 five, on this occasion the entire school, stranded at Weisdale 

 Voe, also in Shetland. 



Pregnancy lasts for about ten months, and it is suggested by 

 Guildberg and Nansen that the young of this species are born 

 in the spring and not later than midsummer. 



Closely allied and similar in appearance and form to the 

 White-sided Dolphin of the Atlantic is Lagenorhynchus 

 obliquidens, found in the North Pacific and south as far as 

 California. 



PEALE'S PORPOISE {Lagenorhynchus australis) 

 Fig. 88. 



Peale's Porpoise which attains an adult length of over 7 feet 

 has a ploughshare-like snout, the beak being defined from the 

 forehead on either side by a distinct depression. The back fin 

 is prominent, recurved and has a bluntly rounded tip. The 

 flippers have a convex front edge, concave hinder edge and are 

 moderately broad at the base. 



There are about thirty teeth in each row in upper and lower 

 jaws; their diameter is about 3 mm. 



The upper surface of the body is dark and the belly white. 

 Dark pigmentation covers the head, encircles the eyes and 

 extends to the lower jaws. A dark streak runs from the base of 



