is free, is
usually very obtuse, or even obsolete. In a paper on the form and
function of the cervical vertebrae published in the _Jenaische
Zeitschrift_ for 1905, Dr O. Reche points out that the shortening and
soldering is most pronounced in species which, like the right-whales,
live entirely on minute organisms, to capture which there is no
necessity to turn the head at all. Accordingly we find that in these
whales the whole seven cervical vertebrae are fused into an immovable
solid mass, of which the compound elements, with the exception of the
first and second, are but little thicker than plates. On the other
hand, in the finner-whales, several of which live exclusively on fish,
and thus require a certain amount of mobility in the head and neck, we
find all the cervical vertebrae much thicker and entirely separate
from one another. Among the dolphin group the narwhal and the white
whale, or beluga, are distinguished from all other cetaceans by the
great comparative length of their cervical vertebrae, all of which are
completely free. In the case of the narwhal such an abnormal structure
is easily accounted for, seeing that to use effectively the long tusk
with which the male is armed a considerable amount of mobility in the
neck is absolutely essential. The beluga, too, which is believed to
feed on large and active fishes, would likewise seem to require
mobility in the same region in order to effect their capture. On the
other hand, the porpoise preys on herrings, pilchards and mackerel,
which in their densely packed shoals must apparently fall an easy prey
with but little exertion on the part of their captor, and we
accordingly find all the neck-vertebrae very short, and at least six
out of the seven coalesced into a solid immovable mass. None of the
vertebrae are united to form a sacrum. The lumbar and caudal vertebrae
are numerous and large, and, as their arches are not connected by
articular processes (zygapophyses), they are capable of free motion in
all directions. The caps, or epiphyses, at the end of the vertebral
bodies are flattened disks, not uniting until after the animal has
attained its full dimensions. There are largely developed
chevron-bones on the under side of the tail, the presence of which
indicates the distinction between caudal and lumbar vertebrae.

In the skull, the brain-case is short, broad and high, almost
spherical,