1883.] Geology and Paleontology. 777 
have scraped leaves from the ends of branches, but the appear- 
ances indicate softer and less tenacious food. Could we suppose 
that the waters of the great Laramie lakes had supplied abundant 
aquatic plants without woody tissue, we would have the condi- 
tion appropriate to this curious structure. Nymphzas, Nuphars, 
Potamogetons, Anacharis, Myriophyllum, and similar growths, 
could have been easily gathered by this double spoon-like bill, 
and have been tossed, by bird-like jerks of the head and neck, 
back to the mill of small and delicate teeth. In order to submit 
the food to the action of these vertical shears, the jaws must have 
been opened widely enough to permit their edges to clear each 
other, and a good deal of wide gaping must, therefore, have 
muscle. The indications are that the external ear was of very 
small size. There is a large tract that might have been devoted 
to the sense of smell, but whether it was so or not is not easily 
ascertained. 
2 
© 
sH 
£ 
O 
oO 
o. 
or 
= 
2, 
ban 
o 
° 
a 
7) 
© 
oy 
ao 
D 
n 
wn 
= 
© 
= 
a 
re 
E 
D 
ct 
ctr 
~~ 
o 
3 
= 
a 
a, 
O 
v 
° 
one | 
the fourth trochanter (third trochanter Auctorum) are attached to 
the proximal caudal vertebrz, one can see the huge tail swing 
from side to side with each advancing step, and create a great 
Swirl in the water. When the bottom was not too soft, they could 
wade to a depth of ten or more feet, and, if necessary, drag 
aquatic plants from their hold below. Fishes might have been 
ie} 
abundant. 
EXPLANATION OF PLATES. 
(All are natural size.) 
PLATE Xvi. Side view of the skull of Diclonius mirabilis. 
“ xvir. The same viewed from above. 
XVII, Inferior view of the same. 
XIX, Fig. 1. View of occipital region of the same. Fig. 2. View of the 
ue extremity of the muzzle from the front. : 
ar he complete iconography of this species will appear in the Report of the United 
tes Geological Survey, under J. W. Powell, now in course of preparation 
-E D. Cope: 
“ 
