WHALEBONE WHALES. 
99 
these Whales are called “ Humpbacks by the whalers. 
They have a wide geographical range. 
The various species o£ Rorquals, Fin-Whales, Fin-backs, 
Finners or Razor-backs, as they are variously called, some o£ 
which are £ound in almost every sea, constitute the genus 
Balcenoptera, characterized by the comparatively small, flat, 
and pointed head, with the throat marked by longitudinal pleats 
capable of distention to £orm a pouch, low back-fin, short, 
narrow, and pointed flippers, with but four digits, coarse and 
short whalebone, and separate neck-vertebrae. 
Rorquals are ^‘clipper-built^’ Whales, adapted for a high 
rate of speed. The largest is Sibbald^s Rorqual {B. sibhaldi), 
which grows to about 100 feet, and is common in the seas 
between Scotland and Norway. Almost of equally colossal 
proportions is the Common Rorqual {B. musculus), found 
throughout the North Atlantic and Mediterranean, and often 
stranded on the English coasts. The skeleton of a full-grown 
animal, 68 feet long measured in a straight line, from the 
Moray Firth, Scotland, where it was captured in 1882, shows 
the osteological characters of this group of Whales, even to 
the small pelvic bone and rudimentary nodule representing 
the femur or thigh-bone. Upon this skeleton has been modelled 
one half of the body to exhibit the external form. The whale- 
bone is in place in the mouth, and the flukes of the tail and the 
dorsal fin are also preserved, and suspended on the wall behind 
the specimen. Balcenoptera borealis, RudolphFs Rorqual, and 
B. acutorostrata, the Lesser Rorqual, are smaller species than 
the last, also stranded in Great Britain, the second more 
commonly than the first. Casts of paddles of Rorquals, 
exhibiting both the external form and the internal structure, 
are displayed on the north wall of the building. 
In a table-case near the large Rorqual are exhibited the 
curious ear-bones of various Whalebone Whales, together with 
a few of those of the Toothed Group. Each genus, if not 
species, can readily be distinguished by the form of its ear 
bones. 
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