tubes enveloping the larynx above, below, and on its sides, and however it may be
bisected, these tubes are always brought into view. No other glandular body is
visible in this larynx.
The foregoing peculiar deeply honey-combed structure of the basal portion
of the inside of the larynx is apparently of rare occurrence among the Cetacea.
I t must not be confounded with the mesial laryngeal sac described by Eschricht and
Reinhardt1 in the Greenland Right Whale {Balcena mysticetus), and by Knox2 in
Bhysalus, Carte and Macalister8 in Balcenoptera rostrata, and by Murie4 in Risso’s
dolphin, Grampus griseus. The two first mentioned of these anatomists do not
describe any peculiarity in the mucous surface lining inside of the laryngeal sac,
neither do Carte and Macalister make mention of any glandular structure in connection
with it in the Pike Whale. Murie, however, in his description of the larynx
of Risso’s dolphin, states that at the lower end of the perpendicular epiglotto-
arytenoid passage the longitudinal folds were here and there interrupted by shallow
glandular pits and depressions, and that among these occurred the orifice into the
laryngeal sac. These glandular pits and depressions alone seem to correspond to
the honeycombed glandular structure figured on Plate XXVIII, fig. 2.
I made repeated microscopic examinations of the structure of the aforesaid
glandular crypts.. One specimen of a vertical section under a low power is shown
in PI. XXXVH, fig. 6. This exhibits a basework of trabecular fibro-elastic tissue,
within the mesh-work of which are here and there dispersed variously sized and
shaped spaces or closed follicular recesses (/.) surrounded by patches of a glandular
stroma (g.). At several points also the connective tissue has muscular packets (m.)
running through it, and traces of capillary vessels (v.) are met with. The free
surface of the membrane is of a velvety, villous or rather papillary nature, studded
with either elevated or depressed simple mucous glands (#.*). Unless it be to
afford a mucous lubrication to the laryngeal surface, it is difficult to assigu any
distinct office to the extensive glandular area under consideration.
Cartilages o f the la/rynx (PI. XXVIII, figs. 2, 8, and 9).—The cartilaginous
framework of the larynx is also found to differ from that of Blatamsta, in the less
development of some of its constituents, notably the cricoid cartilage ; whereas it
closely approximates to the form and structure of the same organ in Globicephalus.
The cricoid cartilage is nearly a facsimile of that of the last named genus
and, like it, has an imperfect ring (fig. 8) ; the two- ends of the cartilage being
separated in the mesial line by a wide membranous interval.
The thyroid cartilage resembles that of Globicephalus and has no anteriorly projecting
body as in the Susu, Blatanista, and is not notched posteriorly. Like this
genus it has a short anterior cornu, behind which the posterior cornu is expanded
into a flat plate; this contracts, however, to a narrow rod as it approaches its
cricoid attachment.
1 Becent Mem. Cet. Bay Soc. Publ. 1866, p. 102. 3 Phil. Trans., vol. 168,1868, p. 238.
2 Cat. Prep. Whale, p. 11. 4 Jonrn. Anat. and Phys., vol. v, 1871, p. 1*27.
T h e b o d y of the arytenoid cartilage of Orcella is a laterally compressed oral,
with a sharp margin directed forwards and a rounded margin posteriorly, by the
upper two-thirds of which it is articulated to the cricoid by a synovial capsulated
joint. The inner surface is concaYe and the external flat. The anterior horn of t e
cartilage is a long, laterally compressed and pointed structure m the upper half o
its extent, hut in the lower half of its surface is thickened and convex from
side to side. I t is connected to the arytenoid body .by fibrous tissue, so that it is
freely moveable on it as is the case in Platwmta. The posterior horn is a downwaid
prolongation of the anterior, and is a rounded bar of cartilage and terminâtes
abruptly in a flattened end at the lower portion qf the penultimate sixth of the
arytenoid body, where it is capped by two small cartilages applied to each other
laterally, succeeded by another cartilage which is wedged in between them and the
last sixth of the arytenoids and curving forwards overlies them. A great part of
the attachment of the aryteno-epiglottidean ligament takes place from the outer
border of these cartilages. Lying between this apical cartilage of the posterior horn
and its fellow of the opposite side occurs a small elongated nodulated cartilage 0 5
inch long and 0-12 inch broad, which assists in filling up the gap that exists between
the arytenoid and ericoid eartilages. I t lies immediately below the mucous membrane
of the cavity, and is crossed by the longitudinal fold of the larynx.
The cartilage of the epiglottis is shorter than the arytenoid horns, but of considerable
breadth, so as to embrace these structures by its lateral margins. I t is
concave from side to side on its laryngeal face and strongly convex on its lingual
surface, expanding above the origin of the hyo-epiglottic muscle, from before
backwards, into a thick club-shaped head with a rather pointed end. Its upper half
arches a little forwards, audits free end is rounded from side to side, and the H H g
scroll-like curving forwards and backwards, terminates laterally in two thick
horn-like projections which turn backwards and support the anterior half of the free
border of the membrane of the arytenoid and of the eartilage of the epiglottis.
■When the muoous membrane is reflected from the side of the aryteno-epi-
glottidean membrane, it is seen to cover a complicated arrangement of valvular
passages separated from each other by piltar-like septa, and ramifying along
the sides of the base of the cartilage of the epiglottis. I t is opposed to the honeycombed
mucous membrane of the inside of the larynx,'and appears to be contmuous
with channels which are displayed here and there surrounding the base of the larynx
above and below when it is cut longitudinally. This arrangement doubtless stands
in some relation to the glandular surface at the base of the larynx internally.
Trachea (Elate XXVIII, fig. 1 1 ).—-This is much more capacious than m Plata-
nista, and its first portion is more imperfect and membranous. Two small flat cartilages
depend from the cricoid, one being placed anterior to its posterior infenor angle,
lying between it and the free end. These are succeeded by two imperfect rings,
each of which encircles ahout one-half of the tube, hut they are separated anteriorly
by a membranous interval, whilst they largely overlap each other behind where the
lowermost one gives off a short offshoot to the right, from its upper border. The thmd