922 General Notes. . [Novemher, 
Plagiaulacide yet known, exceeding the corresponding one of the 
kangaroo-rat of Australia. There are twelve ridges on the side 
of the crown, extending from the base. They are crowded an- 
teriorly and become more widely spaced posteriorly. The ante- 
rior margin is acute from near the base; the latter projects a little 
beyond the root. The most elevated point of the crown is be- 
tween the roots. Ridges fine, enamel smooth. Length of base 
of sculptured part of crown, .0062; elevation of do., .0047; thick- 
ness of do. at base, .0025. The genus and species may be called 
Ftilodus medievus.—E. D. Cope. 
Betopon in New Mexico.—Some years ago! I identified cer- 
tain fossils discovered in North Carolina by Emmons as Belodons; 
and later,’ referred a species found by Wheatley in Pennsylvania, 
to the same genus. I am now ina position to prove that the 
genus ranged over the Rocky mountains, and that there, as in 
other parts of the world, it haunted the shores of the Triassic seas 
and lakes. In the same region a related form, the 7ypothorax 
coccinarunt, existed at the same period.* There are two species 
of Belodon in my New Mexican collections, one as large as the 
gavial of India, the other smaller. In the former the muzzle is 
keeled above, and rises into a crest in front of the nares. In the 
other species the muzzle is subcylindric, and does not rise ante- 
rior to the septum of the nostrils. The larger species I call Bet - 
don buceros ; the smaller one B. scolopax, and define them as fol- 
lows: 
Belodon buceros—Size of the gavial. Muzzle slender, com- 
pressed, with a narrow median superior ridge, rising at the middle 
of the length into a compressed crest, whose summit is in the 
plane of the frontal region. Nostrils a little further anterior to 
the orbits than the diameter of the latter, longer than wide, and 
separated by a thin septum. Orbits round, looking a little up- 
wards, the interorbital region a little narrower than each orbit. 
Preorbital region compressed; preorbital foramen large, inferior. 
The quadrate bones are directed forwards, and their articular faces 
are in the transverse line of the two rather narrow notches of the 
posterior outline of the parietal bone. The auricular meatus is 
bounded by a descending hook-like process; and the squamosal 
bone is continued still further posteriorly into a short triangular 
acute horn. The superior surface of this bone with the parietal and 
frontal, are roughened with tubercles. The palate has a strong 
ridge on each side, so as to be grooved. The posterior teeth have 
compressed denticulate crowns. Tipofmuzzletost. Total length 
preserved, M. .700; length of muzzle to posterior edge of nares, 
.420; do. from latter to lines of anterior edge of orbits, .060; do. 
from do. to posterior parietal notch, .160. Width at posterior bor- 
1 Proceedings Academy of Natural Sciences, Philadelphia, 1866. 
2 Transactions Amer. Philos. Soc., xIv, 1869. 
8 Cope, Report G. M. Wheeler, U. S. Sury. W. of rooth Mer., Iv., 1877. 
