5 18 Proceedings of Royal Society of Edinburgh. [sess. 
portal fissure, it crosses the visceral surface, cuts the margo acutus, 
and is continued across the ventro-lateral surface as far as to the 
boundary of the cephalic surface. When the lobes of the liver 
are undisturbed, the cystic fossa appears to coincide with a part of 
the right lateral fissure ; hut in reality the gall-bladder is 
supported by the customary lobe — the right central. There is a 
fissure — or rather a groove with sharp borders — passing from the 
left side of the cystic fossa to the umbilical fissure. It cannot 
be seen so long as the parts are allowed to remain in their natural 
Off) : lob". 
Fig. 1. 
positions, because of the overlapping of the right central by the 
left central lobe. Attention would not have been called to this 
fissure were it not that some interest is connected with it owing 
to certain observations by Thomson (20). In the course of his 
inquiry into the morphological significance of certain fissures in 
the liver of man, Thomson found a fissure (which he marks “ f ” 
in his figures) passing “from the left edge of the fossa for the 
gall-bladder for a short distance towards the umbilical fissure,” i.e., 
in a position corresponding to the one just mentioned as occurring 
in Cercocebus. In the human subject, apparently, the fissure is 
