432 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
drains the right side, and, like its fellow, enters the ductus Cuvieri at 
the sinus venosus. 
THE DUCTLESS GLANDS. 
THE SPLEEN. 
This organ lies in Amiurus, between the posterior end of the 
stomach and the anterior end of the genital organs. It is in contact 
with the peritoneum covering the ventral surface of the air-bladder, 
and is itself surrounded by peritoneum. The long axis of the gland 
which is parallel to the same axis of the body, measures when the 
organ is distended 20 mm., the short diameter 13 mm. _ It isslightly 
divided into two lobes, a posterior large lobe and an anterior small 
lobe. The surface next the air-bladder is concave, the ventral sur- 
face convex. The right margin, which lies near the median line of 
the body, is thick and rounded, but the gland thins out toward the 
left margin where the points of the lobes nearly touch the left body 
wall. The hilum is on the concave dorsal surface where the artery 
and veins enter together, and run side by side throughout the gland 
until the finer branches are reached. This arrangement agrees with 
that of the higher Vertebrates, but it is not universal in fishes, @. g., 
Anguilla‘, in which the arteries lie across the veins. The vessels 
spread themselves out, fan-like, from three or four trunk-stems, but 
these in the case of the veins do not unite into a single splenic vein 
but enter separately the portal-vein, which runs in immediate contact 
with the surface of the gland. Indeed, one commonly finds three or 
four patches of small openings close together in the wall of the portal 
vein, the larger branches of each centre having entered without join- 
ing. A small vein usually arises from the ventral surface of the 
anterior lobe, and may enter the portal vein direct or join one of the 
mesenteric veins just before its junction with the portal. 
The surface of the spleen presents a perfectly smooth appearance 
in some individuals, while in others raised papille are visible to the 
naked eye. In the former granular-looking nodules can be seen 
thickly imbedded in a clear, reddish matrix, while in the latter they 
are much less distinct. The reason for this ditference will be better 
understood after a description of the internal structure. 
1 C. Phisalex—Structure et texture de la rate, chez l’Anguilla conmunis. Comptes Rendus 
1884, Vol. XCVII., p. 190. 
