Lucas.] 
230 
[October 5 , 
the teeth were taken for that purpose. The spheno-occipital 
suture was found to remain open long after the total obliteration 
of the frontal and parietal sutures, and in old skulls the teeth 
were much exposed by the absorption of the maxillae. Tabu- 
lating the results of applying the above test to the skulls we get 
the following : 
Suture 
closed. open. 
Suture 
closed. 
open, 
S. Wurmbii 3 
5 1 S. satyrus 3 
0 
7 
“ ? 
4 0 “ ? 
3 
5 
9 1 
3 
12 
Thus while only one S. Wurmbii has the suture open — and that 
was but partially so — only three S. satyrus have the same suture 
closed, so that while there are no young animals among the first 
named species, there are very few old ones in the second. Mr. 
Hornaday used the confluence, or near approach of the temporal 
two ridges, as the most apparent character of S. Wurmbii. ISTow in 
two of the six male S. Wurmbii these ridges were respectively 5 
and 12 mm. apart at the nearest points, and the animal in which the 
ridges were the more distant was the only one in which the spheno- 
occipital suture was open. In one male S. satyrus — so-called in 
Mr. Hornaday’s note book — the temporal ridges approach to 
within 10 mm., and this is the oldest male S. satyrus. Of the 
four female S. Wurmbii two possessed confluent temporal ridges 
and the other two had them 16 and 21 mm. apart. Of the 
eight female S. satyrus two had the position of the ridges indicated 
merely by a faint line. In the others they were separated re- 
spectively 20, 23, 30, 40, 45, and 60 mm. and the three specimens 
in which the temporal ridges converge most were the three oldest 
skulls. 1 Respecting the lambdoidal prominences we find that they 
are hardly noticeable in skulls where the temporal ridges are wide 
apart, and that closer convergence of those ridges is accompanied 
by an increase in the size of lambdoidal projections until in skulls 
where there is a slight sagittal crest there is also a well marked 
1 It is true that in three females the temporal ridges are some distance apart where 
the specimens are indisputably old, but we might expect this from the well known 
law that the adult female retains the characteristics of the immature male, and it is 
noteworthy that no young female — or for that matter no young male — has ever been 
called S. Wurmbii. 
