“ moniliform tube” in tbe mesentery of JBal&noptera sibbaldii and otber concurrent
arrangements in tbe vascular system. Dr. Muñe also, in researches on the
Organization of the Ca’ing "Whale1 (Globicephalus melas), has directed attention to
peculiarities in the vascular and lymphatic system of that genus. The views propounded
by these authors do not entirely coincide, though each admits a probable
certain connection between the blood and the lymphatic systems. The fact of
Orcella, and the possibility of other Cetaceans besides those mentioned, possessing
structures modifying the more direct circulation of the blood among the viscera thus
acquires additional importance, which future researches may render more clear and
explain the physiological function performed by these modifying structures.
Owing to the heat of the weather and to other causes incident to the difficulties
of dissecting in a tropical climate, I could not follow thoroughly the distribution
of the cceliac axis. I was, however, very soon struck by the fact that the arteries
supplying the stomach were at intervals dilated into large sacs, from which small
branches diverged which communicated with the main channels and their sacs
by minute orifices, as is illustrated in fig. 8.
Large vascular channels penetrated the walls of the stomach between the
second and third cavities, and I shall presently more particularly allude to
their connection with the glandular structure. The walls of the vessels were, as
mentioned by Professor Turner, of great thickness, and this was the case not
only in those of great calibre, but equally in the minute arterial twigs, given off not
only to the stomach, but to the spleen, the pancreas, and the whole of the lymphatic
glands. Indeed, when preserved in alcohol, they appeared as a vast ramification of
hard cords penetrating everywhere gastric and surrounding tissues, and even carried
onwards towards the mesentery. In most respects, therefore, they corresponded to
Turner’s description, and accorded with the character given of the “ monilifonn
tube” (I. c.). ■
Peculiar gland of stomach in Orcella.—Lying in the angle formed by the
oesophagus and the second stomach, and hidden in its lower third by the third stomach,
and covered above by the liver, is a large gland, which is closely related to the
coronary artery and vein of the stomach. Its position is indicated by g. and ¡pointer,
fig. 5, PI. XXVTI. I t is somewhat triangular in form, and measures 3 inches
long and broad. Its base or hilus is placed towards the superior branch of the
coronary artery, the anterior surface of which it wholly invests. Its lower third
is also placed over the inferior branch of the coronary artery and vein. Its lower
border is loosely adherent to the pancreas and its posterior surface to the right
extremity of the first stomach, whilst its apex, where the vein and artery which
traverse it quit the gland, is firmly adherent to the apex of the first stomach at
its right side, where the oesophagus ends and the stomach begins. Its base is loosely
adherent to the vena cava inferior, and the hepatic artery and portal vein enter
the liver to the right of the gland. I t is invested by a strong fibrous capsule,
through which and between it and the cortical substanoe numerous blood-vessels
1 Trans. Zool. Soo. 1873, vol. viii. p£. 370, ,&o.
ramify. The fibrous capsule also sends outwards to the medullary substance strong
fibrous bands, which unite with similar bands derived from the hilus. The cortical
substance is about a quarter of an inch in thickness, and is of looser texture around
its capsular than its medullary border which is fibrous in texture; the fibrous bands
generally indicating the presenoe of arterial twigs provided with enormously thick
coats. The gland is attached all along its under surface to either side of the
inferior division of the coronary artery and vein, while its base, direoted upwards,
is attached along the superior branch of that artery which it invests. At the
beginning of the inferior division of the ooronary artery two branches are given off
for the supply of the gland, one passing into the pferior fifth of the gland, as a
distinct branch, whilst the other, proceeding from the opposite side of the vessel,
runs right through the base of the gland, viz., parallel to the superior coronary
artery and in front of and above the superior coronary vein, and inosculating with
the superior coronary artery after it issues from the gland. These vessels, artery
and vein, are embraced in the firm fibrous capsule, except below the vein where the
fibrous character is lost.
As to the intimate structure of the above mentioned stomach gland, I have
given its naked-eye appearance when sliced through in fig. 7, PI. XXVII.
Beneath its strong fibroid capsule, is firmish gland-like substance (g.) pierced
here and there by thick-walled blood-vessels (a.) of an arterial character, and wide,
irregular, elliptical, or irregularly contoured venous channels (».). In one part of
it there is a much firmer, tougher, almost tendinous-like mass (£.) and much less
porous than the neighbouring tissue. The glandular substance itself in all essentials
agrees with an ordinary lymphatic gland, with moreover a feature peculiarly
its own, viz., an enormous number of good-sized, even large, vascular channels,
besides a plentiful supply of tributary capillaries. See fig. 3, PI. XXXVII, and
also compare figs. 4 and 5 in same plate, being sections- of a somewhat similar
gland in the lung of Flatanista and Orcella. Thin and partially transparent sections
of these glands made in a variety of directions and examined under low
and high microscopic powers show everywhere a vast number of capacious blood-
channels. These are by no means regular in calibre or direction, but branch hither
and thither, and from them also proceed branches and branchlets of very irregular
character. Very fine twigs seem to pass direct to those of larger calibre, and
veins and arteries seem mingled promiscuously. This vascular plexus has not
then the character of what is understood by rete mirabile, where the vessels maintain
a nearly uniform calibre and run close together in parallel lines; but, on the contrary,
it has a want of uniformity. Some of their walls are thin, as if alone bounded
by a cellular layer; others are much thicker walled. Encompassing these vessels
in every direction, and indeed simply allowing them to permeate it, is a trabecular
frame-work of variable degrees of thickness and fineness and the meshes of which
are of all sizes and shapes, though, where the intermediate more pulpy substance
has been pressed out, the reticulation has a somewhat stellate configuration. This
last is due to more condensed enlarged portions of the membrane giving off radii