ar vertebra
the vessel divided into the common iliacs. The _art. sacri media_, its
continuation, continued its course protected by the V-bones, and giving
off branches corresponding to the intervertebral spaces.

_Brain and Nervous System._--The erectile tissue surrounding the spinal
cord and origin of the spinal nerves in the Cetacea did not extend into
the interior of the cranium. The entire encephalic mass weighed 2-1/2
lbs.: cerebrum, 2 lbs.; cerebellum, 1/4; pons and medulla, 1/4 = 2-1/2.
Compared with a drawing of Camper of the _Delphinus Phocaena_, the brain
was found to differ remarkably, in being much broader in the line of the
middle and posterior lobes. In no animal did I ever find the fibrous
structure of the brain so well marked; and this extended to the
cerebellum[D]. I give here some measurements of the brain, which may be
of use to future observers. The brain is short from before backwards,
but broad transversely:--

Antero-posterior diameter 5-2/8 inches.
Breadth 8 inches.
Greatest breadth of the cerebellum 4 inches.
Length of the cerebellar hemisphere 4-6/8 inches.
Depth of ditto 3-2/8 inches.
Weight of the encephalic mass 2-1/2 lbs.
Depth of the interhemispherical fissure 1-2/8 inches.
Length of the corpus callosum 1-7/8 inches.
Weight of cerebrum 2 }
Weight of cerebellum 0-1/4} = 2-1/2 lbs.
Weight of the pons and med. oblongata 0-1/4}

_Nerves._--The 7th pair was found to be unexpectedly large and firm,
including both portions. The anterior roots of the spinal nerves were
far more numerous than the posterior or dorsal.

_Muscles._--The panniculus carnosus, strong and fleshy, extended nearly
over the whole trunk. The recti abdominis were powerful, and attached
inferiorly in this way:--A portion runs to the pelvic bones; a much
stronger to a strong aponeurosis, situated between the anus and the root
of the tail.

The erector muscles of the spine (sacrolumbalis, longissimus dorsi and
multifidus spinae) weighed fully 16 lbs. They had but slender costal
attachments; but their spinal (small delicate tendons) were innumerable.
The scaleni were very large; and the vessels held the same relation to
them as in man. The serratus magnus was comparatively small. The larger
rhomboid had no spinal attachme