1902 - 3 .] Abdominal Viscera of Cercocebus fuliginosus, etc. 533 
A more careful examination reveals the tetrahedral shape ; the 
•only surface which is in any way ill-defined is the basal. The 
phrenic surface (superficies phrenica) is by far the most extensive, 
almost equalling in area the combined gastric and renal surfaces, 
because of the flatness of the whole spleen. Strictly speaking, the 
term “ phrenic ” does not apply to the most ventral part of the 
surface, since it is in relation to the abdominal wall, and not to the 
diaphragm. The gastric surface (superficies gastrica) is deeply con- 
cave, and, in point of area, comes next to the phrenic surface. The 
renal surface (superficies renalis) is also very concave. Except 
where it is separated from the phrenic surface, the basal surface 
(superficies basalis) has no definite boundaries ; but it may be dis- 
tinguished from the adjacent gastric and renal surfaces by its 
irregularly convex character. It is related to the splenic flexure 
of the colon. 
The margo intermedius is very obtuse, and has the hilum 
running along it. Both the margo crenatus and the margo obtusus 
are thin and sharp. The former carries two notches ; the latter, 
one (PI. III. fig. 7). It seems highly probable that in all mammals, 
crenations, when they do occur, are more likely to be found on thin 
borders than on thick ones. And this apparently applies also to 
those cases where notches appear in spleens usually free from them. 
In an earlier paragraph it has been stated that notches are now and 
then observed on the spleen of the horse. When this is the case, 
the notches are invariably on the thinnest border — that corre- 
sponding to the margo obtusus of man. So far as memory serves, 
I should say that notches on the spleen of the dog occur indiffer- 
ently on either of the two thin borders, as they do in this particular 
specimen of Lagothrix. 
The apex of the spleen of Lagothrix is obtuse. The only other 
angle which is at all distinct is the anterior (ventral) basal angle. 
The internal (mesial) basal angle is indistinguishable, and its 
position can only be determined upon by observing the point of 
junction of the gastric, renal, and basal surfaces. 
It is possible that the pathological change in the liver may have “told back ” 
upon the spleen, and so have produced some increase in size from venous 
engorgement, though this was not suggested to the naked eye. Microscopic 
sections were not made. 
