40 Guide to Whales, Porpotses, and Dolphins. 
somewhat variable in length, but the bony union of the two 
halves of the lower jaw is short (less than one-fifth the entire 
length of the jaw), and the teeth are very small and numerous, 
the number of pairs in each jaw varying from 30 to 50. The 
stuffed specimen exhibited (fig. 25), which is the type of the 
species, and came from South Africa, was presented by Captain 
Heaviside to the Royal College of Surgeons, whence it was trans- 
ferred in 1841 to the Museum; skulls of this and other species of 
the genus are shown in the wall-case at the south end of the 
gallery, which also contains a stuffed specimen ‘of the Malay 
species known as Prodelphinus malayanus. 
‘ Two North Atlantic Cetaceans, the White-beaked 
preeear ge Dolphin (L. albirostris) and the White-bellied 
olphin. Dolphin (L. acutus), both of which occasionally 
put in an appearance in British waters, constitute the genus 
Lagenorhynchus, which is best characterised by the numerous 
vertebrae (80 to 90) in the skeleton; these having short bodies 
and very long and slender vertical and transverse processes, 
or spines. The White-beaked Dolphin, which takes its name 
from its white lips, is represented by the skeleton of a female 
from the south coast of England, and likewise by a coloured cast 
of the head exhibited on the east wall of the building. The latter 
specimen, like most of the casts on the walls, was presented by 
the Government of the United States of America. 
The remaining groups of long-snouted Dolphins 
Pe are chiefly distinguished from one another and 
orpnin. the preceding genera by the characters of the 
teeth and skeleton——characters which cannot be given in detail in 
this guide-book. As an example of the first genus, we take Elliot’s 
Dolphin (Steno perniger). In the somewhat extensive genus of 
which this species (fig. 26) is an Indian representative, the beak 
is of great relative length and narrowness, being very distinct from 
the hind part of the head, and separated by a groove from the 
forehead. The two halves of the lower jaw have an exceedingly 
long union; and the teeth, which may have either smooth or 
grooved crowns, vary from 20 to 35 pairs in each jaw. The 
present species is distinguished by the beak being more than three- 
fifths the length of the skull, and also by the smooth crowns of 
