304 



MR. R. I. POCOCK ON THE 



anywhere between its anterior extremity and the paroccipital 

 process, it presents the appearances which misled Flower and 



Text-fiii-ui-e 1. , 



pen 



'I'P^ 



(Copied from Flower's figures, P. Z. S. 1869, pp. 16-17.) 



A. Right half of the base of the skull of the Tiger (Felis tigris) with the bulla laid 



open to expose the inner chamber (^c), with the septum or partition (s.) 

 ascending to the periotic {per.), and the orifice (o.) leading from the inner to 

 the outer chamber between the septum and the periotic ; e., internal orifice 

 of eu.stachian tube ; ov., foramen ovale ; fp., foramen lacerum posticum ; 

 ■po., paroccipital process ; m., mastoid ; earn., external auditory meatus. 



B. Section of the auditorj' bulla of the Tiger, ic, inner chamber ; oc, outer 



chamber with the orifice (o.) between the two and the septum (s.) dividing 

 them; tr., half the tympanic ring in the outer chamber; earn., external 

 auditory meatus ; per., periotic. 



Mivart. The greater part of the space is occnpied by a single 

 large cavity, which opens by a wide cleft in front into a smaller 



Description of Text-figure 2 {continued). 



C. Left bulla enlarged, with the posterior portion of the septum, marked s in fig. A, 



cut away to show the cavity of the inner chamber and the antero-interual 

 portion of the bulla also cut away, and the carotid canal {c.) laid open ; the 

 passage leading from the outer to the inner chamber between the periotic 

 {per.) and the septum marked by an arrow. /., foramen piercing sphenoid 

 and corresponding with the anterior carotid foramen of Mongooses ; fp., fora- 

 men lacerum posticum. Other lettering as in figs. A & B. 



D. Part of the right side of the skull viewed from the occipital aspect, with the 



bulla laid open from behind to show the inner chamber with the periotic 

 {per.), carrying the fenestra rotunda, partially blocking the orifice between 

 the two chambers divided by the septum (s.). Other lettering as in fig. A. 



E. Right bulla of the Spotted Hya;ua {Crocuta crocuta). A line drawn between 



"the paroccipital process {po.) and the stylomastoid foramen {st.) would 

 mark the edge of the partition between the two chambers. 



