146 D. M. S. Watson — New Cynodont from Cape Colony 



procumbent aud lies close up to the syuiphysis. Ig is a considerably 

 smaller tooth, also of oval sectiou, which lies close behind and 

 outside I|. The canine is a larjie tooth whose root, the only part 

 preserved, is of oval section. It seems to have pointed directly 

 upwards, and iramediatelj' follows Ig. Behind the canine is a long 

 diastema, which is followed by a series of cheek teeth, six of which 

 are preserved before the fracture whicli terminates the specimen. 

 These teeth are small, single-rooted, and narrow from side to side ; 

 the root is deep and closely fits its alveolus. Only 3, 4, and 5 show 

 anything of the crown, and even these are mutilated ; they seem to 

 be much alike, and a description of the last may serve for all. The 

 crown is of an irregular oval shape, widest in front, where it is about 

 three-quarters of its length. There are four cusps arranged longi- 

 tudinally and forming the outer side of the tooth ; the summits of 

 the anterior three of these are broken, but it is certain that the first 



Fig. 2. The fourth and fifth molars of the right side of the lower jaw of 

 Pacliygenelus monus, gen. et sp. nov. x 8. Inner aspect. 

 ,, 2a. The fifth molar viewed from above. 



Avas much the largest and that they gradually declined in size and 

 height to the fourth. On the inner side is a strong cingulum, whose 

 position will be best understood from the figures. This shows 

 a very faint crimping, as if in the descendants of our animal it might 

 have developed cusps. 



The systematic position of this specimen is difficult to determine ; 

 it is either a ' Cynodont ' or a mammal. The occurrence of a splenial 

 suggests reference to a former group, although it is exceedingh' 

 probable that a splenial did occur in the most primitive mammals. 



The only known 'Cynodont' from the same horizon is Tritherlodon 

 riconi, Broom, of which only upper molars are known ; the type 

 differs from ours fundamentally in the structure of the molars, which 

 are transversely widened. All the other ' Cynodonts ' differ in 

 having more than two lower incisors, the Bauridse offering the best 

 comparison in that their incisors are large and somewhat procumbent. 



