upper lip has a sharp margin, and the interval between it and the line of upper
teeth is concave from without inwards, broad behind at the last tooth and narrowing
anteriorly to a point. A deep furrow runs from the symphysis of the lower jaw to
the base of the tongue, and numerous folds pass from it along the sides of the
tongue, to the angle of the mouth. The deep furrow and the folds in these localities
like others presently to be described on the palate in the faucial and pharyngeal
regions and oesophagus are all represented in the foetus, so that they are structural
characters developed to confer expansibility on these portions of the digestive tube.
The tongue of this genus (figs. 1 and 2, t.) is free as far back as the beginning of
the posterior fourth of the interdental space of the lower jaw, and in this respect
it differs remarkably from the character of this organ in Cetacea generally. I t is
a long spatulate structure with sharp free borders which shelve rapidly downwards
and backwards, and it is slightly contracted opposite the angle of the mouth
and somewhat dilated anterior to that, terminating in a rounded but pointed end,
external to which the margin is crenulated for a short distance both in the foetus
and in the adult. Behind the angle of the mouth, it is concave from before
backwards and slightly raised and swollen into two basal eminences. In the foetus
the anterior portion is more or less concave from side to side, which is to a certain
extent also the character of the organ in the adult. In the foetus there is
a fold corresponding to the frænum linguae, but it disappears when it is laterally
stretched and returns when the parts regain their natural position. In the adult,
however, there is no fold determinable in this locality. In the foetus the organ
measures 4 inches from the anterior end of the fraenum epiglottidis to the tip,
and it is free for one-third of its extent. In the adult, the tongue to its
base is 6'85 inches long and l"-90 in its greatest breadth. In the foetus there
is no indication of a raphe, and indeed so far from such a furrow existing, thè
middle of the tongue anteriorly is slightly raised, as two shallow and feeble furrows
run backwards from the first crenulation external to the triangular tip.
In the adult, however, a short raphe begins opposite the angle of the mouth,
and running backwards for about one inch terminates in a transverse fold, which
curves forward from angle to angle of the mouth and corresponds to the limit
of the extrinsic muscles of the organ, but which does not show in the foetus.
On either side of the raphe there are many wavy longitudinal folds which become
curved on the attached portion of the tongue, anterior to them the convexities of
the curves being forward, and these folds are feebly marked in the foetus. Immediately
posterior to the deep transverse fold there are similar feebler folds which also
-exist in utero, and before the basal eminences in the foetus, the dorsum of the
organ, as in the adult, is covered with convoluted folds. I have failed to detect
the orifices either of sublingual or submaxillary glands or the openings of any glands
whatever on the under surface and sides of the free portion of the tongue. In the
adult the margins of the tongue superiorly and the whole of the dorsum, within an
inch of the tip, as far back as the transverse fold, are covered with the orifices of
mucous glands. Behind the transverse fold, less numerous, but much larger and
patulous orifices occur all over the posterior portion of the organ, and these are the
terminations of large racemose glands. The openings are chiefly confined to the
hollows between the folds or convolutions. Only filiform papillæ occur on the
portion of the tongue anterior to the transverse fold, but behind that, as far back as
the frænum epiglottidis, the dorsum is sparsely covered with pedunculated or sessile
papillæ. The former are club-shaped eminences of the mucosa clad with filiform
papillæ, and the longest measures about 0-20 of an inch in length, of which its
head forms about 0"‘10. The sessile papillæ are the most prominent, and they are
generally situated either singly or in pairs at the mouths of the larger racemose
glands, where also but more rarely occur some of the pedunculated kind.
Palate (Pl. XXVII, fig. 1, p.).—Its surface is triangular, convex from side to
side, and perfectly smooth in its anterior or interdental portion. I t is thrown into
transverse folds behind this in the region of the angle of the mouth, and into
longitudinal folds in the remainder of its extent. The interdental portion is, however,
traversed by a straight sharp longitudinal furrow, which begins with a bifurcate end
embracing a triangular eminence at the anterior margin of the palate. I t is deeply
marked in the adult and also in the foetus, in which in the region of the transverse
folds, it is interrupted by a transverse slit or mucous crypt (e.) situated over the end
of the palatal portion of the maxillaries in a line with the inner angle of the mouth.
I can throw no light on the nature of this recess beyond that it is lined with the
mucous membrane of the palate, which, however, loses its pigment at the margin
of the sac. I t is 0'40 inch long, and leads into a short cul de sac 0T2 inch
in length. The median furrow again shows itself a short way behind the slit and
runs backwards for some distance.
At about 0*9 inch from the anterior margin of the posterior nares in the adult, and
0'5 inch in the foetus, there are two crescentic folds of the mucous membrane occurring
on. either side of the mesial line of the palate separated from each other in the
adult by an interval of 0'45 inch and in the foetus by an interspace of 0T inch. The
convexity of the folds is directed forwards, and each defines a recess in the mucous
covering of the palate 0-2 inch in breadth in the foetus, and but only a little larger
in the adult. In the left recess of the foetus there is a nipple-shaped structure surmounted
by a small round sessile papilla, and surrounded at its base by a distinct
fold* I t is not so well marked on the right side, which is due, however, to the more
relaxed condition of the mucous membrane. In the adult when these recesses
are laid open they are found to be studded over with small lobules or amygdaloid
bodies. The structure, position and contents of these crypts lead to the supposition
that they are probably the representatives of the tonsils. If this prove to be the
case, they are the first instance on record of the occurrence of these glands in the
Cetacea. On the palate, external to and behind the tonsils, are large openings of
racemose mucous glands and sessile and pedunculated papillæ, the same as occur on
the tongue.
Before leaving the palaté, it may be stated, that in the foetus the line of teeth
is indicated immediately internal to the groove that defines the palatal surface from