is a smooth concave surface (fades tvodilcavis) [11] over 

 which the squamoso-mandibularis muscle works, above this 

 again is that aspect of the suspensory ramus which forms 

 the floor [12] of the post-tympanic notch. In the depth of 

 the notch is a well defined groove (sulcus oolumeUac auris) 

 [13] which is converted by a membrane into the columella 

 canal, and lodges the columellae auris. Turning now to 

 the lateral aspect of the bone, it is seen that the flange 

 which forms the outer portion of the temporo zygomatic 

 surface for the greater part of its length, forms also the 

 lower and anterior wall of a large oval tympanic fossa [14] 

 of which the upper portion is excavated out of the otic 

 ramus. The post-tympanic notch extends so far into the 

 fossa that the outer end of the columella sulcus is almost 

 in its centre. At the postero-inferior angle of the otic 

 ramus, there is commonly developed a tubercle (tubcrcuJuni 

 post-tumpanieitm) [15] for the attachment of the tough 

 membrane which completes the fossa across the notch. 

 The condyle [16] is elongated from side to side and concave 



the long axis. 



The otic and suspensory rami and pedicle are completely 

 hoiindor/oiis with those three pyrtions or' die amphibian sus- 

 pensoriuni. 



The Pterygoid (Os pterygoideum) .Figs. 36 and 37] an 

 elongated flattened bone, may he conveniently divided for 

 descriptive purposes into an anteri"r plmrv ;:-■■;-! p ■>! t.' m A 



portion V, (/jiffs Ixtsil unijxniiat) diverging from that axis. 

 The pharyngeal portion forms with its follow a bony roof 

 to the pharynx immediately liehiml the nasopalatine fossa 

 and between the two zygomatic fossae, its anterior margin 

 articulates with vomer [1], pa hi : _. e ,-vgoid pro- 



