306 JAMES ROLLIN SLONAKER 
It will be seen that the cervical vertebrae are constant and 
conform to the mammalian type and that the other groups vary. 
The discrepancies which are noted for the same genus may be due 
to the fact that the different authors may not have had the same 
species under observation or that a variation occurs; more likely, 
the first supposition obtains. 
The transverse processes of the vertebrae of the species under 
observation are relatively short. This permits a greater flexi- 
bility of the spinal column, which makes it possible for the mole 
to turn more easily in its burrow and go in the reverse direction. 
Owen (’66) describes ‘antigenous hypophysial ossicles’ inter- 
posed beneath the interspaces of the bodies of the lumbar verte- 
brae. This is verified by True (’97). I find six or seven such 
ossicles in Scalops aquaticus and eight in Scapanus latimanus 
(fig. 3 and fig. 6, Os). The posterior one is the largest and is 
located at the junction of the posterior lumbar with the first 
sacral. The series gradually diminishes in size until the most 
anterior element is barely visible. These species also have 
ossicles situated on the ventral side at the interspaces of the 
caudal vertebrae. In younger animals they consist of a pair 
of almond-shaped bones arranged parallel with each other and 
with the axis of the tail. In old animals these are usually fused 
by median outgrowths and form a single H-shaped ossicle. 
The most anterior are the largest and occur beneath the inter- 
vertebral space of the first and second caudal vertebrae. They 
gradually diminish in size posteriorly until they disappear. Sca- 
lops has five such pairs of ossicles and Scapanus eight. Similar 
ossicles are found in other tailed mammals. 
I am at a loss to determine what the function of these ossicles 
may be. The position and shape of those in the lumbar region 
suggest that they may act as a sort of pivot or fulcrum to in- 
crease the possible lateral movement. In the caudal region 
there is nothing which would indicate this possible function. 
The fact that tendons seem to be attached to them indicates 
that they function in movement of the tail. 
The cervical and thoracic vertebrae are without spinous pro- 
cesses, permitting greater flexibility of the animal. The lumbar 
