922 General Notes. [ November, 
lax the ridges are continued to the posterior edge of the crown, 
and in Ctenacodon the ridges do not extend on the sides of the 
crown. In Hypsiprymuus the ridges are vertical. 
Char. spectf. The tooth is much larger than that of any of the 
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 1n 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 i 
other parts of the world, it haunted the shores of the Triassic seas 
and lakes. In the same region a related form, the Typothorax 
coccinarum, 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 1s 
keeled above, and rises into a crest in front of the nares. In the 
other spécies the muzzle is subcylindric, and does not rise ante- 
rior to the septum of the nostrils. The larger species I call Belo- 
don buceros ; the smaller one B. scolopax, and define them as fol- 
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 10 the 
plane of the frontal region. Nostrils a little further anterior to 
the orbits than the diameter of the latter, longer than wide, an 
Separated by a thin septum. Orbits round, looking a little up- 
wards, the interorbital region a little narrower than each eine 
Preorbital region compressed ; preorbital foramen large, inferior. 
The quadrate bones are directed forwards, and their articular ces 
are in the transverse line of the two rather narrow notches of the 
posterior outline of the parietal bone. The auricular meatus sh 
: e 
tions Amer, Philos. Soc., xIV 
e 
1 Proceed 
 ® Transac .y 
port G. M. Wheeler, U. S. Surv. W. of tooth Mer., 1V-> 1877+ 
ings Academy of Natural Sciences, Philadelphia, 1866. 
