1909. | ANATOMY OF CERTAIN UNGULATA. 187 
cecum. It is important to note that this character is apparently 
a constant one, which I have used above (p. 181) in distinguishing 
other Antelopes. The ansa paracecalis of Moschus is not dealt 
with by either Flower or Garrod. It is remarkable in that it is 
bent upon itself four times to form a small spiral, which is quite 
as conspicuous a spival as is that of the Lemurine subfamilies 
Galagine and Lorisine, and may even, quite possibly, really be 
the equivalent of that colic loop—the true ansa coli dextra of the 
Rodents being in that case absent from the Lemurs. 
In Gazella rufifrons (a female) the ansa paracecalis is roughly 
of the shape of the letter “‘m.” That is to say, it consists of two 
parallel loops. Immediately after the ansa paracecalis the colon 
diminishes suddenly in calibre, and enters the region of the 
colic spiral or ansa coli dextra. This is a comparatively simple 
coil. It is only a little more complicated than that of JMZadoqua 
described on page 189. Cut right across, the colon would be 
divided seven times, counting the straight tracts which enter and 
which leave the coil. As usual, the small intestine is festooned 
along the colon after the colic spiral. The colon in this region 
passes almost completely round the circumference of the abdominal 
cavity, and forms nowhere any special loops. The duodenum where 
it turns upon itself is fixed, as in other Antelopes, to the colon 
itself, and not to the mesocolon 
With regard to the colic spiral, it is to be noted that it belongs 
to the type of Cephalophus ma: gwelli. Bub the loops do not form 
a regular watchspring as in those Artiodactyles already con- 
sidered. For the terminal loop of the spiral does not lie entirely 
within the coil but extends beyond it. 
Dr. Lonnberg comments upon the remarkable colic spiral of 
the Musk-Ox*. Im addition to the spiral coil there is a 
separate loop formed by the outgoing limb of the spiral, as is 
depicted in his figure. It seems to me that this state of affairs 
is comparable to the presence in so many Rodents of two anse 
coli, the dextra and sinistra. The two are close together in 
Squirrels, for example. If one of these—and they are frequently 
of different sizes—were converted into a spiral, we should have 
a condition produced which would be precisely like the Musk-Ox. 
For the lengthening of the one loop—already the longer of the 
two-—to form a spiral would bring it about that the shorter ansa, 
remaining a simple tubular loop, would be affixed to the back or 
to the front of the spiral, as is actually the case in the Musk-Ox. 
There is, however, no need to theorise ; for the Rodent Dasyprocta 
punctata shows exactly the same conditions as those met with in 
the Musk-Ox. In this species * there is a short spiral and also a 
simple loop closely affixed to it. I take it that this is a simple 
form of the complex spiral and associated Hore} found in the 
Musk- Ox: 
But woaly in one specimen out of two; the other showed a single spiral only. 
PZ 
aK 
+ P. Z. 8, 1900, p. 152, fig. 7. 
