PAR Se eee oO 
235. 
APPENDIZA: 
Art. LXII.—Notice of new Jurassic Mammals; by Professor 
O. C. MARSH. 
Among the fossils from the Atlantosaurus beds of the Rocky 
Mountains recently received at the Yale College Museum, are the 
remains of several] mammals distinct from woe hitherto de- 
scribed by the writer.* These include two new genera, and 
four species, which are described below This material throws 
much light on the specimens previously discovered, and also 
shows some a ope characters not before seen in mammals. 
Allodon laticeps, gen. et sp. nov. 
The type specimen of the present species is a left upper jaw, 
with molar and premolar teeth in good preservation. This 
ee indicates that the skull was a short and broad one. 
he anterior half of the zygoma is in we ia and ~~ that the 
arch was strong, and widely expanded. ere are five premo- 
inner side, and rounded extern wily The two true molars 
strongly resemble those of Microlestes, and hence are similar in 
form to the lower molars of Plagiaulax and Ctenacodon. The 
crowns are very low, and are divided into an outer and an 
inner half by a deep worn groove. The last molar has its lon- 
_ gitudinal groove in a line with the inner Ara of the other 
f teeth. The principal measurements of this specimen are as 
ollows 
e occupied by seven posterior teeth. .--.---- — 
_ of two true molars. ---. - Os 
Distance from orbit to margin of | upper jaw - SS, 
Extent of maxillary above second premolar-- ---- ae 
*. This Journal, vol: xv, p. 459, vol. xviii, pp. 60, 215 and 396, and vol. xx, p. 
