322 
A MEMOIR UPON THE GENUS 
situated on a line anterior to the canines. The form of the nasals is very character- 
istic of P. megarhimis, distinguishing it from any other species of this group. They 
are much elongated and convex at the middle portion, becoming wider and 
strongly depressed at the extremities which are expanded and broader than 
the iniddle portion. This character of the nasals distinguishes them from 
those of the other species of the subfamily. The posterior portions of these 
hones are broad and they articulate laterally with the maxillaries by broad 
23lates. Their jtosterior extension is on a line with the anterior j)art ol the 
orbits. The nasal notches ai'e rather short, hut higher than in P . paliidosus ; 
their superior and inferior outlines are more sinuous than in the latter s^iecies ; the 
part of the nasal notch formed by the maxillary is concave anteriorly and then rises 
gradually to the superior termination. The maxillaries take a rather larger share 
in the formation of the nasal notches than the premaxillaries, whose superior limit 
is above the posterior border of the first jiremolar. 
Figures. — Outline of Nasals. 1. Palseosyops paludosus. 2. Palveosyops meg- 
arhimis. 3. Limnohyo}^^ laticeps> One-quarter natural size. 
Proboscis . — There is a wide difference of opinion among paleontologists as to 
the presence or absence of a proboscis in certain groups of fossil animals. As it is 
important to decide whether or not an animal bore a proboscis, I shall treat 
the question as thoroughly as possible and give my own conclusions upon the 
subject. They are derived from the study of a number of different groups 
of animals which are said to be jjroboscis-bearing. Prof. Cojje' in summing up the 
affinities of the Dinocerata as com2)ared with those of the Proboscidea savs “ the 2)os- 
session of a proboscis is proven by the extreme shortness and , stoutness" of the free 
portion of the nasal bones, by the very short cervical vertebra?, and by the fact that 
the nasals and premaxillary bones are deeply excavated at their extremities, with 
surrounding osseous eminences for the origin of the muscles of the trunk. ” 
On the other hand. Prof. Marsh,= in his restoration of Dinoceras says : “ the 
neck was long enough to permit the head to reach the ground, and hence a pro- 
boscis was quite unnecessary. The horizontal narial opening, the long overhang- 
'Tertiary Vertebrata, i)age 511. 
^Monograph of the Dinocerata, page 166. 
