0. C. Marsh—New Orders of Jurassic Mammals. 235 
Arr. XX VIUT.—WNotice of Jurassic Mammals representing two 
New Orders ; by O. C. MARSH. 
found, and others are different from any now known. 
is new material is all from the Atlantosaurus beds, in 
essentially the same horizon which furnished the earlier speci- 
mens. The general resemblance of the American forms to 
those from the Purbeck of England becomes still more evident 
in the remains here described. , 
Diplocynodon victor, gen. et sp. nov. 
One of the largest mammals yet discovered in the Jurassic 
beds of this country or of Europe is represented by various 
remains of several individuals, found in the same locality. 
The most characteristic of these specimens is a right lower 
jaw, with most of the teeth in position, and well preserved. 
The general characters of this jaw are well shown in the 
figure below. 
Ls 
Right lower jaw of Diplocynodon victor, Marsh. Outside view; twice natural size. 
a, incisor, b, condyle; c, coronoid process: d, angle. 
This jaw is quite distinct from anything hitherto described, 
and exhibits several characters of special interest. re were 
at least three incisors, directed well forward. The canine is 
very large, and is inserted by two fangs. This important fact 
has suggested the name of the genus. The molar series con- 
s 
: J by 
six premolars. The second of these is smaller than t 
and the others gradually increase in size. The last true molar 
was smaller than the others) The crowns of these teeth are 
* This Journal, vol. xv, p. 459, 1878; vol. xviii, pp. 60, 215 anf 396. 1879. 
