heiver-Dolphins. 29 
differing somewhat in quality from that of the Cachalot; and a 
few years ago these Whales were extensively hunted for the sake 
of this product. The skeleton exhibited is that of a female or 
young male; while the skull beside it (fig. 10) is that of a very old 
male taken in the Orkneys. The huge size and close approxi- 
mation of the premaxillary crests of the skull characteristic of 
aged individuals of that sex are well shown in the latter specimen ; 
in the females they remain throughout life comparatively small 
and widely separated. The external form of the Bottle-nose is 
exhibited by means of a miniature model of an adult male. 
Dolphin-like Certain Cetaceans from the Miocene Tertiary 
Peaked! Whales. deposits of Europe and North America, de- 
scribed under the name of Hurhinodelphis, 
represent an extinct family—the Huwrhinodelphide—which is 
evidently related to the Ziphiidx, but possesses certain distinctive 
peculiarities. Among these characteristic features, are the small 
size of the pterygoid bones, the long, toothless premaxille, and the 
Dolphin-like prenarial region of the skull. The premaxille form 
the greater portion of the very long beak; the maxille carry from 
37 to 60 conical teeth ; and the skull is of the general type of that 
of the Ziphiide, in some cases slightly convex, in others with a 
bold transverse crest. 
The group, of which no examples are exhibited in the building, 
forms a primitive type evidently related to the Ziphiide, but none 
of the species at present known can be regarded as ancestral to 
the latter. 
Three living species of Dolphins, respectively inhabit- 
ing the rivers and estuaries of India, the Upper 
Amazon, and the Rio de la Plata, represent two 
distinct families. These are shown in the case on the left side of 
the vestibule of the Whale Room. The first of these is the 
Platanistide, including only the Susu (Platanista gangetica) of 
the Ganges, Indus, and Bramaputra, which ascends those rivers 
almost to their sources, but never passes out to sea. In common 
with the next family, the Susu (fig. 14) has eight double-headed 
ribs and a long beak; its costal cartilages ossify late in life; the 
petrosal and tympanic bones are connected with the skull mainly 
by ligament; the temporal fossa is large ; all the cervical vertebrae 
are free; teeth are present in both jaws; and the flippers are 
River- 
Dolphins. 
