AMBLYPODA. 
185 
discovered the near affinity between these suborders. As regards the 
possession of a proboscis, there is every reason to believe that some of the 
species possessed one, though it may have been short as in the Tapir, while 
it is possible that in others it was wanting, or not more developed than in 
the Hog. 
The first attempt to define the Binocerata as an order of Mammalia 
Avas made by Prof 0. C. Marsh, of New Haven, in a paper published some 
time subsequently* to my essay quoted above. The characters which he 
brought forward, and which iiad mostly already appeared in the descriptions 
of species published by him and by myself, are the following: “1. The 
absence of upper incisors; 2. The presence of canines; 3. The presence 
of horns; 4. The absence of large air-cavities in the skull; 5. The malar 
bone forms the anterior portion of the zygomatic arch; 6. The presence of 
large postglenoid processes; 7. The large perforated lachrymal forming 
the anterior portion of the orbit; 8. The small and horizontal nareal orifice; 
9. The greatly elongated nasal bones; 10. The premaxillaries do not meet 
the frontals; 11. The lateral and posterior cranial crests; 12. The very 
small molar teeth and their vertical replacement; 13. The small lower jaw; 
14. The articulation of the astragalus with the navicular and cuboid bones; 
15. The absence of a true proboscis.” 
This heterogeneous list of characters could not define any natural group, 
as many of them are of not more than generic or family value.f Several of 
the most important are not shared by the genus Corypliodon^ a form at that 
time apparently unknown to Professor Marsh, but which clearly belongs to 
tlie same order of Mammalia. My conclusion has been that the Binocerata 
do not alone constitute an order of Mammalia, but that they form a division 
of an order wiiich includes also Coryphodon, and doubtless many other 
little or unknoAvn types, Avhose position is, as I first stated, between the 
Prohoscidla and the Perissodaciyla, but which has no affinities with the Ar- 
tiodactyla, as has been asserted. 
Full descriptions of the species and genera of this order first appeared 
in my essay, “On the Short-footed Ungulata of Wyoming”, above quoted 
* The extra copies of this paper bear date January 28, 1873. 
t As I pointed out in an article in the American Naturalist, May, 1873. 
