SEALS— DOLPHIN 243 



seal is still abundant, but in the North Sea it is less plentiful than formerly 

 and from many places has quite disappeared. In the North Atlantic this species 

 keeps exclusively to the shore, and is never found on ice-floes in the open sea. 

 From the shore it ascends many of the larger rivers, having been found in North 

 America far up the St. Lawrence. Preferring sheltered channels and shallow 

 bays, it chooses such rocks and sand-banks as are isolated from the shore, where it 

 may be met with at low tide all the year round, for it does not migrate. 



Another British species is the grey seal {Halichoerus gryjius), 

 attaining a length of from 8 to 9 feet, and silvery or yellowish grey 

 in colour, generally with blackish or smoky brown irregular spots, which are 

 sometimes so large as to cause the whole coat to be nearly black, though occa- 

 sionally these are absent. The under-parts are lighter. This is essentially a 

 northern species, most common in Britain in the Hebrides. 



Although often seen along the Scandinavian coast as far as Finmarken and 

 around Iceland, it is apparently unknown in Spitzbergen and the other European 

 Arctic Islands. Its occurrence on the east coast of Greenland is doubtful, but on 

 the west side of that country it is found as far north as Disco Island, Sable Island 

 off the coast of Cape Breton forming its southerly limit. 



Very distinct is the monk seal (Monachus albiventer), inhabiting: 



Monk Seals. . 



the Mediterranean and Black Sea, as well as the eastern Atlantic, 



inclusive of the coasts of Madeira and the Canaries. Like the West Indian seal of 



the same genus, it-is remarkable on account of being a native of the warmer seas. 



This seal is 8 feet or more in length, and in colour is dark brown and grey above, 



and whitish below. It is distinguished by having the first and fifth toes of the 



hind-feet longer than the rest, as well as by the presence of small or rudimentary 



nails to all the toes. 



The West Indian monk-seal (M. tropicalis) was discovered in August 1494, 



when the sailors of Columbus killed eight of these " sea-wolves " as they called them 



on the rocky island of Alta Vela off the coast of Hayti. In colour this seal is 



glossy black when young, gradually turning to dark brown with a greyish tinge on 



the sides and lower-parts, and becoming more or less yellowish white with age. 



Its teeth are well developed and apparently adapted for crushing shells as well as 



catching fish, but little has been ascertained as to its feeding habits beyond that, 



like others of its family, it is able to fast for months when captured. Though 



known for centuries, and its haunts being neither inaccessible nor distant from the 



habitations of man, there is a strange want of information regarding this species, 



which has so decreased in numbers that it is becoming, or has become, extinct. 



As breathing air and producing living young which are suckled 

 Dolphin. ft l . , . 



by the female parent, whales and dolphins, collectively forming the 



Cetacean order, come within the category of mammals of the littoral zone. All are 

 able to remain a long time under water, and breathe rapidly by raising the blow- 

 hole slightly above the surface. In the group of toothed whales, which includes 

 the sperm-whale and all the dolphins and porpoises, the blow-hole is single. One 

 of the most familiar representatives of this section of the group is the common 

 dolphin (Delphinus delphis), which grows to a length of about 1\ feet, and is 

 generally dark grey above, and white or whitish below, with grey or pale bands on 



