1909. | ANATOMY OF CERTAIN UNGULATA. 185 
remaining subdivisions of the Ungulates help us in this search. 
In neither Hyraxz nor Hlephas are there any beginnings of the 
spiral. It is true that the simple colic loop of the Perissodactyles 
(found in all the families of Perissodactyla) may be regarded as 
the progenitor of the spiral; but this is going too far back in the 
evolution of the spiral. What is wanted is a simple spiral of a 
negative character which with further growth might evolve into 
either type. Now it is interesting to find that this form of spiral 
—precisely what is wanted to serve as a starting point—is to be 
seen in those Lemurs with a simple colic spiral, i. e., Galago*, 
Loris, Perodicticus, and Nycticebus. 1t will be seen from an in- 
spection of the figure that this simple spiral can be easily regarded 
as a three quarters of a circle spiral with the apex of the spiral 
pointing upwards, and of course with the outer limb of the 
descending part of the colon turned towards the cecum. On the 
other hand, it may be regarded as a commencing spiral of half 
a turn with the apex pointing downwards. In this case it 
obviously belongs to the other series, for if the spiral were 
continued so that the apex pointed upwards, the limb forming 
the apex and nearest to the cecum would be that of the inner 
limb of the loop. It is perfectly clear, therefore, that a growth 
of this rudimentary spiral could produce either of the two types 
of Artiodactyle spiral with which I am concerned in the present 
communication. This is of course not tantamount to insisting 
upon any close relationship between the Ungulates or the Artio- 
dactyle Ungulates and the Lemuroideay. But it is at least 
important to note that while the only widely distributed sub- 
families of the Lemuroidea have preserved without variation an 
archaic and indifferent form of spiral, the most archaic Artio- 
dactyles have not the simplest form of spiral conceivable. So 
far, therefore, it would appear as if the colic spiral as such had 
been inherited by the Artiodactyles. It is, of course, not at all 
certain that the single loop of the Perissodactyle Ungulates is 
the homologue of the Artiodactyle spiral; it may represent the 
ansa paraceecalis of the latter. 
The facts detailed under the above descriptions of the anatomy 
of Antilocapra may be supplemented by some account of the 
intestinal tract in other Artiodactyles which I have had recently 
the opportunity of examining at the Prosectorium. Among 
those the most interesting perhaps is that of the Musk Deer 
(Moschus moschiferus) . The viscera of this animal, including 
the alimentary tract, have been described by Sir W. H. Flower § 
and Prof. Garrod ||. The cecum is figured by Flower, but the 
colon is not specially described. A footnote adds that in 
* For non-diagrammatic figure see Beddard, P. Z. S. 1908, p. 578, fig. 114. 
+ Moreover, the apparently similar colic spiral found in certain Rodents (Hydio- 
cherus, Dasyprocta, and Cologenys) requires further consideration trom this point 
of view. 
+t A female dissected Dec. 21, 1908. 
§ P. Z. S. 1875, p. 159. || P. Z. S. 1877, p. 287. 
