PHYVSETERID.A£ 249 
to the apex. Upper edge of the mesethmoid forming a roughened 
irregular projection between the narial apertures, inclining to 
the left side. Mandible exceedingly long and narrow, the 
symphysis being more than half the length of the ramus. Vertebree: 
C7,D 11, L 8, C 24; total 50. Atlas free; all the other cervical 
vertebre united by their bodies and spines into a single mass. 
Eleventh pair of ribs rudimentary. Head about one-third the 
length of the body; very massive, high and truncated, and rather 
compressed in front; owing its huge size and remarkable form 
mainly to the accumulation of an oily substance secreted by 
the lining membranes of great cells surrounding the narial passage 
and filling the large hollow on the upper surface of the cranium 
and overlying the rostrum. The single blowhole is longitudinal, 
slightly sigmoid, and placed at the upper and anterior extremity 
of the head to the left side of the middle line. The opening 
of the mouth is on the under side of the head, considerably behind 
the end of the snout. Pectoral fin short, broad, and obliquely 
truncated. Dorsal fin a mere low protuberance. 
The only representative of this genus is the Cachalot or Sperm 
Fic. 83.—The Sperm Whale (Physeter macrocephalus). 
Whale (P. macrocephalus, Fig. 83), one of the most colossal of 
animals, quite equalling, if not exceeding, the Greenland Whale 
in bulk. The length of the full-grown male is from 55 to 
60 feet, but the female is stated not to reach more than half 
that size. The general colour of the surface is black above and 
gray below, the colours gradually shading into each other. — The 
Sperm Whale is one of the most widely distributed of animals, 
being met with usually in herds or “schools ” in almost all 
tropical and subtropical seas, but not occurring, except accident- 
ally, in the Polar regions. Not unfrequently specimens appear 
on the coasts of the British Isles, but only as solitary stragglers, 
or as dead carcases, floated northwards by the Gulf Stream. It 
is remarkable that every one of these of which we have an accurate 
record has been an old male. The food of this Whale consists 
mainly of various species of cephalopods (squid and cuttle-fish), 
but fish of considerable size are also eaten. The substance called 
“ambergris,” formerly used in medicine and now in perfumery, 
is a concretion formed in the intestine of this Whale, and is found 
