CHAP. XIIL] THE GAT'S PLAGE IN NATURE. 483 



auditory bulla, and the condyloid foramen is concealed within the 

 foramen lacerum posterius. There is either no glenoid foramen 

 or it is minute. The mastoid process is quite indistinct, or but little 

 prominent. The bony meatus auditorius externus is either very 

 short extending but little outside the tympanic ring (as in Yiverra, 

 Fig. 199) or if, as in the Suricates, it is prolonged, its floor is 

 medianly fissured. 



The next family is that of the Hyaenas, HYJENID^E, which also 

 contains the curious and aberrant South African mammal, the Aard- 

 vark (Proteles) an animal erroneously supposed by some naturalists 

 to be related to the dog. 



In this family the teeth are either, as in the hyaenas, remarkable 

 for their strength and cutting power, or, as in Proteles, for their 

 extreme weakness. In the hyaena there are four upper premolars, 

 all sectorial, especially the hindmost, which is much like that of the 

 cat, as is also the minute, solitary upper tubercular molar. In the 

 lower jaw there are three premolars and one molar all sectorial 

 like those of the cat, though less perfectly formed for cutting, 

 because the hyaena's teeth are broader and stronger, and more suited 

 for the bone-crushing action in which they are employed. The 

 Aard-vark has four weak, small molar teeth in either jaw, each such 

 tooth being separated by a diastema from the tooth nearest to it. 



As to the structure of the skull, the hyaenas have a smooth, oval, 

 prominent bulla, which is perfectly simple within its cavity, not even 

 showing a trace of a septum for its division into two chambers. 

 Yet, as in the Yiverrines, it is considerably more prominent posteriorly 

 than in front, so that if a septum was developed, the chambers would 

 probably be placed one in front and one behind. There is no ali-sphenoid 

 canal. The carotid foramen (Fig. 202, car) is small, and situated a 

 little behind the middle of the inner margin of the bulla. The par- 

 occipital process is spread out over the posterior surface of the bulla, 

 but forms also a rounded prominence projecting backwards (p). 

 The mastoid process is also slightly prominent. The bony meatus 

 auditorius externus is short, yet the anterior portion of its floor is 

 produced outwards as a rather pointed process. The condyloid 

 foramen is concealed, and the glenoid foramen is minute or absent. 



Proteles agrees with the hyaenas in these cranial characters, except 

 that in it the bulla is divided by a septum into two chambers one 

 being quite anterior and the other posterior and that the mastoid 

 and paroccipital processes do not stand out from the skull. As to the 

 generative organs, Cowper's glands and a salient prostate are present 

 in both Proteles and Hycena, while no bone has been observed in the 

 penis of either. In both, also, the caecum coli is simple and very 

 small, and there are large scent-glands. In both, also, there are 

 normally not less than fifteen dorsal vertebrae. 



The third family, CRYPTOPROCTIDJS, contains only a single species 

 namely, a fierce animal (of the size of a large cat) to which the 

 natives of Madagascar give the name " Foussa." 



It is an animal much like a cat, but with a longer head. It has 



i i 2 



