1S72.] G. E. Dobson — Osteology of Tricenops persicus. 137 



Tr. persicus Ph. la/rvata, 



inches. inches. 



Extreme length of skull, 0.85 095 



Breadth between upper margins of zygomata, 0'30 050 



Breadth across nasal prominences, 0*28 - 28 



Greatest vertical height of zygoma, - 15 010 



Length of zygoma, - 18 - 23 



Length of bony palate, laterally, 024 023 



Width of basi- occipital between the cochlese,. . . 004 010 



Length of base of skull from posterior margin 



of palate to edge of foramen magnum, - 37 0"43 



"Width of the base of the skull behind poste- 

 rior roots of zygomata, - 32 0*42 



The auditory bullce 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 

 cochlea? of Phyllorhina, and resembling more closely the same parts in Hhi- 

 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 Phyllorhina 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 Phyllorhina larvata the precondyloid 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 jPhyllorhina 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 



