24. Guide to Whales, Porporses, and Dolphins. 
nostrils; some of the cervical vertebre are fused together; the 
two halves of the lower jaw may have a long or a short union; 
the blow-hole is situated on the left side, and is longitudinal or 
oblique, with its concavity turned backwards; the stomach is 
muscular (which it is not in the Ziphiide); and the teeth in the 
lower jaw are numerous. There is no enamel on the teeth of the 
Cachalot, but this is present in those of the extinct genera in 
which funetional teeth are developed in the upper jaw, the number 
in the premaxille being limited to three pairs. It may be added 
that in the existing Sperm-Whale teeth of considerable size—an 
inch or so in length—are embedded in the gums of the upper jaw, 
but never attain full development. 
The Cachalot is one of the mostly distributed of all Whales, 
occurring usually in herds or ‘ schools’ in most warm seas; but 
ranging in summer so far north as the Shetlands and Iceland. 
The species occurs from time to time in the Mediterranean, as is 
indicated by the incised slab of whalebone referred to under the 
heading of the Greenland Whale (p. 14), and also by a skeleton 
in the Cambridge University Museum, prepared from a_speci- 
men taken off Lipari in the year 1902, a second and larger 
individual being seen at the same time. Old males are much 
larger than females, and have the front of the head abruptly 
truncated. The chief food of the Cachalot consists of cephalopods 
(squid and cuttlefish), some of enormous size. 
The position of the external nostril near the anterior end of 
the head is exceptional. In the model the tube represents the 
course of the left nasal passage, which is alone pervious, and 
shows the direction of the jet of vapour, by which the “ blowing’ 
or breathing of the Sperm-Whale may be distinguished from that 
of other Whales (in which it ascends vertically) at a distance. 
The want of symmetry of the nasal region of the skull, and the 
reduction in the size of the right nasal aperture are noteworthy. 
A great part of the space above the skull is occupied by the 
receptacles for the spermaceti, which is a liquid oil at the 
temperature of the living animal, but solidifies on cooling, and when 
refined constitutes the white, crystalline spermaceti of commerce, 
used for candles and ointments; its use in the economy of the 
animal is unknown. 
A near relative of the Sperm-Whale is the Lesser Cachalot 
(Kogia), mentioned on page 26. 
The extinct genera include Balenodon (Sc wae etus, Hoplocetus, 
’ 
