242 BULLETIN OF THE 
These may be properly termed anterior and posterior tympanic vacu- 
ities, or foramina, corresponding to the foramen lacerum medium and 
foramen lacerum posterius basis cranw of anatomists. Plate IL. Figs. 9, 
10, a. 
2. ‘Orbito-nasal” includes the vertical plate of the palatine, and 
the margins of the palatine, maxilla, alisphenoid, orbitosphenoid, and 
frontal, at their lines of juncture, as also the combination of certain 
foramina. Plate II. Fig. 7, a, 6. 
3. “Palatine” designates the anterior and posterior portions of the 
palate, one or both. Plate I. Figs. 1, 2, a, 6. 
4, “Facial” includes the side wall of the face, the latero-nasal por- 
tions of the maxilla, and the anterior root of the zygoma. Plate IL. 
Fig. 8, a. Plate I. Figs. 3, 5, a, 6. 
5. The “ Occipito-squamosal” is the space comprehended between the 
supraoccipital, exoccipital, and squamosal. Plate II. Fig. 11. 
6. The “Squamosal” and “ Parasquamosal” are indicated by the 
terms used. Plate I. Fig. 4, d. 
The cranial vacuities in the various orders of the Mammalia occur 
as follows. 
Monorremata. — The skull of the Echidna presents no vacuities. In 
the Ornithorynchus, there are relatively large anterior and _ posterior 
deficiencies, the first representing the foramen ovale, and the second 
the jugular and the preecondyloid foramina combined. There are also 
small ones in the basisphenoid. 
Marsupiauia.— Many of the Macropodide have large posterior palatine 
vacuities. These are present also in Phascolarctos (Plate I. Fig. 1, a), 
in the Dasyuride (Plate I. Fig. 2, a, 6), and in the Peramelide. Pera- 
meles lagotis has a large oval vacuity which extends from the second pre- 
molar to the penult molar, and posterior to this are found several small 
ones. In the Didelphide there are large posterior palatine vacuities. 
Epentata. — This order is singularly free from cranial deficiencies. 
In the Dasypodidz the posterior tympanic vacuity, or foramen lacerum 
posterius, is somewhat enlarged. Among the Sloths, Cholepus hoffmanni 
presents considerable deficiencies in the basi-sphenoidal region. 
CutropTera. — In a few genera, notably in Pteropus, the posterior 
tympanic vacuities are large. 
Insectivora. —In some of the Erinaceide, the post-tympanic are 
large, while there are also extensive post-palatine vacuities, especially in 
Erinaceus europeus. In Sorex, large latero-basal ones are found, and 
Tupaia has a large longitudinal central deficiency of the malar, in addition 
to the palatal vacuities. 
