BRITISH MAMMALS 
Genus Hyperoodon. 
THE BOTTLE-NOSED WHALE. 
Hyperoodon rostratum, Miiller. 
Plates 44-45. 
This species possesses a single pair of teeth, which are hidden in the 
gum at the point of the lower mandible, and are invisible in the living 
animal. 
The snout is lengthened in the form of a pronounced beak ; above 
this the frontal part of the head rises, in the old males almost per- 
pendicularly, but in the females and young with a more sloping outline. 
The adult males attain a length of 30 feet, the females about 24 feet. 
The bones of the neck are united. The flippers and dorsal fin are small, 
the latter being placed far back. 
The drawing of the head of this Whale (Plate 44) taken from a cast 
in the British Museum (Natural History) shows one of the gular grooves, 
a pair of which run along the lower jaw. 
The Bottle-nosed Whale shows great variation in its colour. 
According to Captain D. Gray (Proceedings of the Zoological Society 
for 1882), "They vary in colour from black in the young to light brown 
in the older animals. The very old turn almost yellow, the beak and 
front part of the head being nearly white, with a white band round their 
necks ; all of them are greyish white on the belly." 
The species is found in considerable numbers in the North Atlantic, 
and it penetrates as far as the margin of the ice in the Arctic seas. 
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