1872.] G. E. Dobson — Osteology of Tri-cenvps persicus. 137 
Tr. persicus Ph. larvata 
inches. inches. 
Extreme length of skull, 0-85 0 95 
Breadth between upper margins of zygomata, 0'30 0’50 
Breadth across nasal prominences, 0'28 0'28 
Greatest vertical height of zygoma, 0'15 0T0 
Length of zygoma, 0'18 0'23 
Length of bony palate, laterally, O' 24 0 23 
Width of basi-occipital between the cochleae,... O' 04 010 
Length of base of skull from posterior margin 
of palate to edge of foramen magnum, 0'37 0 43 
Width of the base of the skull behind poste- 
rior roots of zygomata, 0 - 32 0'42 
The auditory bullw ossecE are very large and prominent ; the cochleae 
are deeply grooved externally by the intervals between the spiral chambers, 
contrasting with the smooth external surface of the much less prominent 
cochleae of Bhyllorhina, and resembling more closely the same parts in Ilhi- 
nolophus. 
The par-occipital processes are long and slender, club-shaped, narrow 
above, expanded beneath, directed downwards and slightly forwards, termi- 
nating in a small, acutely pointed projection directed forwards, supporting 
the inferior surface of the petro-mastoid. In Bhyllorhina the par-occipital 
processes are very short and blunt ; in Rhinolophus long and slender, direct- 
ed downwards and forwards, slightly thickened beneath. 
There is a minute precondyloid foramen on each side, and in front of, 
and external to it, a wide opening — having for its anterior boundaries the 
petro-mastoid and cochlea — the jugular foramen. There is no distinct 
carotid foramen. In Bhyllorhina larvata the pteeondyloid foramen is sepa- 
rated from the jugular opening by a considerable interval ; the latter is 
small, circular, and occupies the angle between the petro-mastoid and cochlea. 
The basi-sphenoid is perforated, posteriorly, in the middle line by an 
oval aperture, a defect of ossification, represented in Bhyllorhina by a circu- 
lar thinning of the roof of the basis cranii in the same situation. Between 
this aperture and the glenoid fossa is a circular opening, the foramen ovale, • 
placed posterior and slightly external to the sphenoidal fissure. More pos- 
teriorly and externally, behind the glenoid fossa, separated from the petro- 
tympanic bulla by a narrow bony process, a large post-glenoid foramen exists, 
while immediately external to and above it the squamosal is perforated by a 
small venous canal directed upwards. 
The roof of the meso-pterygoid fossa is pierced posteriorly by two small 
foramina placed one on each side of the middle line, and separated by an 
exceedingly narrow bony lamella, and similarly in front, near the junction 
