SS 
eee AEREE NTI E a = a i 
ba 
nas tk cE a i e Meee POSS eae a a at 
1878.] Geology and Paleontology. 325 
the true one.” There is no doubt, however, that the greater part 
of the cast of this region, which I have made, belongs to the olfac- 
tory lobes, and for the following reasons: e excavation was 
conducted with the greatest care, occupying more than two weeks, 
and the sandy matrix was removed grain by grain. No trans- 
verse cribriform plate was found, and no osseous body interrupted 
the matrix posterior to the anterior extremity of the chamber 
cast. No longitudinal septum divided the olfactory chambers 
until the entire thin edge which marks the fundus of the groove 
in my figure! was reached. It is not probable that these struc- 
tures had been present and been lost. The position of this cham- 
ber is much posterior to that of the nasal cavities in Mammalia 
generally, being above the posterior part of the pterygoid plates, 
instead of between the posterior (tapir) or anterior (hog) regions 
of the orbits. The septum observed is doubtless that whic 
divides the right and left olfactory lobes. Its sides are smooth as 
far as the inferior termination of the chamber as figured. I have 
not followed out its superior extremity owing to the appearance 
of delicate osseous pieces which may belong to the ethmo- 
turbinal. This is the first interruption of the olfactory chamber 
met with. What the homology of the contents of this space 
with the olfactory lobes and nerves of later mammalia may be, 
remains to be ascertained. 
Prof. Marsh’s last paper on this family is, however, not free 
from what I should call, were I to use his phraseology, “ glaring 
errors.” He denies that the ectocuneiform ‘bone is in contact 
with the astragalus, which is palpably the case (see my Fig. 12, 
Pl. LIX, in the volume iv, Paleontology of the U. S. G. G. Survey 
under Lieut. G. M. Wheeler). He also represents the temporal 
fossæ as converging towards a sagittal crest behind the orbits, 
whichis not the case. The temporal fosse are entirely lateral as 
in Uintatherium. See my Plate LII of the work cited. Rather, 
however, than assume that these are “glaring errors,” I await 
solution of the question as to whether two different genera of 
Pantodonta, i. e., Bathmodon and Coryphodon are not under con- 
sideration. 
subject as left by Hébert, was added by myself between that date 
and the spring of 1876. In April of that year I exhibited to the 
Academy of Natural Sciences of Philadelphia, and a few days- 
after to members of the National Academy at Washington, the cast 
of the brain of this genus. Prof. Marsh’s paper appeared after — 
1 Wheeler’s Report PI. LI, Figs. 2-6. : 
