DOLPHINS. 
113 
In the next Case are the skeleton and some skulls of another 
freshwater Dolphin, Inia geojfrensis, from the Upper Amazon and 
its tributary streams, and also of a very remarkable species, Pon- 
toporia blainvillii, from the estuary of the Rio de la Plata, of very 
small size, with exceedingly long and slender jaws and the most 
numerous teeth of any mammal, sometimes as many as 60 on each 
side of each jaw, or 240 in all. Both of these have some rela- 
tionship with the Platanista, although in many characters they 
approach the next group, or true Dolphins. 
Family Delphintd^. 
A very numerous group, composed of the animals commonly 
called Dolphins and Porpoises, although some of the larger mem- 
bers are also dignified by the name of Whales. Skeletons of most 
of the genera are exhibited, and also a large series of skulls (those 
of the smaller species being in the Wall-Cases at the end of the room 
nearest the door). There are also stuffed specimens of many 
species, and papier-mache models of others, showing very well the 
external form and colour of the animals when fresh. 
The principal genera are : — 
Delphinus. The true Dolphins, Bottle-noses, or, as they are more 
commonly called by seafaring people, Porpoises,'’^ are found in 
considerable abundance in all seas. They are all among the 
smaller members of the Order, none exceeding 10 feet in length. 
Their food is chiefly fish, for the capture of which their long, 
pointed beaks, armed with numerous sharp-pointed teeth, are well 
adapted; but some appear also to devour crustaceans and mollusks. 
They are mostly gregarious, and the agility and grace of their 
movements in the water are constant themes of admiration to the 
spectators of the scene when a ‘‘ school of Porpoises is observed 
playing round the bows of a vessel at sea. The old genus is 
now much subdivided — Lagenorhynchus, Tursiops, Pi'odelphinusj 
Sotalia, Stem, Cephalorhynchus, being names applied to its various 
sections ; Delphinus being now generally restricted to the common 
Dolphin of the Mediterranean, D. delphis, and its immediate allies. 
This species is met with, though not frequently, on the English 
coast, a stuffed specimen from Cornwall being shown in the 
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