HISTORY OF MARINE MAMMALS—ABEL. ATT 
though costly, medicine, and was universally considered to be the 
horn of the fabulous unicorn. In 1749 Leibniz gave a highly fantastic 
picture of it in his “ Protogzea.” 
To the great group of dolphins belongs the harbor porpoise 
(Phocena), which is abundant in almost all (northern) seas. This 
small dolphin, ?. phocena, which is only 1} meters (5 feet) long, is 
noteworthy on account of the fact that small bony tubercles are to be 
found on the front margin of the dorsal fin and flippers, which 
tubercles are remnants of the dermal armor borne by its ancestors. 
The harbor porpoise often ascends streams a long distance, and has 
frequently been met with in the Elbe, Schelde, Thames, and Seine. 
Numerous genera and species of dolphins are recognized, as this 
family includes a great variety of forms. The killer whale (Orcinus) 
and the blackfish (Globiocephalus) belong to this family, as well as 
the common dolphin (Delphinus delphis), which was known to the 
ancients and is common in all seas. 
The peculiar Ganges dolphin (Platanista), which lives in the great 
rivers of India, stands quite by itself. This dolphin is entirely blind, 
due, probably, to its ving continuously in turbid waters. The eyes 
are only as large as peas, and have no lenses. The beak of this 
dolphin reminds one forcibly of the jaws of the gavial, or Ganges 
crocodile. 
We shall now endeavor to summarize the common habits of the 
whales. They live exclusively in the water. No whale is fashioned 
to move on land. Progression takes place only through the powerful 
turning about of the great caudal fin, with its flukes, which acts hke 
the screw at the stern of a ship.t. The body is more or less fusiform, 
and the swiftest swimmers have a high dorsal fin, as well as a pointed 
snout, which cuts the waves like the prow of a ship. The arms and 
hands have been transformed into flippers, which serve as a steering 
apparatus. Since the work of propelling the body falls on the caudal 
fin, or flukes, the hind limbs have become superfluous, and have been 
reduced to rudiments which lie deep in the soft parts. (Figs. 25 and 
26.) The pelvis has lost its connection with the vertebral column, and 
in the dolphins consists of a very small, slender rod of bone. In the 
bowhead, in addition to a larger remnant of the femur, a smaller rem- 
nant of the tibia is present. (Fig. 25, T.) 
The dentition is adapted to environmental conditions in a remark- 
able manner. As the food is swallowed whole, the teeth have only the 
function of fangs to seize and hold the prey. 
The number of teeth varies greatly. It ranges from 246 in the long- 
beaked dolphin to two in the bottle-nosed whale. The snout is short 
@ This idea, which is not original with Professor Abel, is, I believe, incorrect. 
All cetaceans, and certainly the smaller ones, progress solely by upward and 
downward strokes of the flukes—F. W. T. 
