PAL^OSYOPS LEIDY, AND ITS ALLIES. 
323 
ing nasal bones and the well developed turbinal bones are likewise positive proof 
against the presence of such an organ.. There is some evidence of a thick flexible 
lip, resembling perhaps that of the existing Rhinoceros. ” 
We see from the above quotations that these authors hold diametrically oppo- 
site views I’egarding the occurrence of a proboscis in the Dinocerata. My 
own studies u])on the subject lead me to coincide with Prof. Marsh’s views, and I 
consider that the Dinocerata were unprovided with a true proboscis. In order to 
form an opinion as to the absence or presence of a proboscis in the Ungulates I 
submit the tbllowing statement. The European Palamtheroids form one of the 
most intei’esting series in this connection and Prof. Gaudry' has expressed the opinion 
that in P . crasswn a proboscis was wanting. He observes that in the last named 
species the nasal bones are large and project farther anteriorly than in P. medium. 
and consecpiently the jDi’oboscis was more reduced. It appears to me tliat this char- 
acter should guide us in deciding whether or not a fossil Ungulate bore a proboscis. 
As already noticed in Palceotherium crassum, the nasals do not reach as far forward 
as the premaxillary suture, and the nasal notches are well developed. On the other 
hand in P. mediu7n the nasals are much more reduced, their anterior extremities 
reaching to about the middle of the nasal notches. In P. magmwi the abbreviation 
of the nasals is carried still farther, and in tlie recent Tapir we see their greatest 
reduction. Coincident with this shortening of the nasal bones in the Tapir is 
the development of a large proboscis. In the Elephant, the most specialized animal 
as regards a proboscis, we have the process carried to its farthest point, the 
the nasal bones being very small and placed in nearly the middle of the skull. 
In this animal the proboscis is enlarged into a trunk. Accordingly the presence of a 
proboscis seems to depend on the reduction or shortening of the nasals, and their 
being placed farther back than usual on the skull. With this recession of the 
nasals from the premaxillary region there is, of course, more mobility given to this 
part of the face, and consequently, where the nasal tips are placed far behind as in 
the Tapir, a large j^roboscis is develojoed, this organ being movable in all directions. 
If the nasal tips extended as far forward as the premaxillary suture this free play 
of the proboscis would be impossible. The mere shortening of the cervical region is 
not the cjiuse, or at least not always the cause of an extension of the nasal region into 
a proboscis. In the Rhinoceros, for example, which is a more bulky animal, having 
the neck shoider than the Tapir, there is no j)roboscis developed, whereas in the 
more slightly constructed Taj^ir a well develojjed proboscis is present. In a group 
separated widely from the Ungulates, viz : the hisectivo7'a, there are two 
genera, Macroselidcs and Myogale, Avhich have a well developed proboscis. I 
have not had an opportunity to examine the structure of the skull in these genera, 
but owing to their small size I should think it would not be specially modified 
as in the Peiissodactyles. In the genus Cystophora {Pinnepidia) the nasals are 
'Les Enchainments du Monde .tninial, etc., page 46. 
43 JOUR. A. N. S. PHILA., VOL. XI. 
