ANCODON GOEEINGEI. 181 



M. 8424. Palatal region o£ skull with teetli. On the right side pm. i and m. 1-3 are preserved, on 

 the left m. 3 is wanting. Right side figured PL XVIIT. fig. 3. In the figure pm. 3 is 

 drawn in outline from another specimen (M. 8425). 



The fourth premolar consists of an outer crescentic cusp and a large inner rounded 

 tubercle ; the cingulum is well developed on the inner side. This tooth resembles the 

 fourth premolar of the other species of Ancodon and differs from that of Brachyodus in 

 the absence of a postero-internal cusp. The molars increase regularly in size from 

 before backwards. They are quadrate in outline, and as in the other members of the 

 family are composed of five main cusps, three anterior and two posterior. These cusps 

 are lower and much less distinctly selenodont than in the other species of Ancodon 

 except A. porcinus, Gerv., a species which Lydekker * has shown to be intermediate in 

 molar structure between the typical species of Ancodon and Anthracotherium. The 

 outer wall is strongly folded into a W-shaped ectoloph, the parastyle and mesostyle 

 being very prominent in all the molars, while in m. 3 there is a large metastyle also. 

 The cingulum is strongly developed and continuous round the anterior and inner sides 

 of- the teeth. This also seems to be the case in A. porcinus and in Brachyodus, while in 

 the more hypsodont species of Ancodon the cingulum is almost wanting on the inner 

 side of the teeth, and in Anthracotherium it is absent on the inner side of the inner 

 main cusps. The dimensions (in centimetres) of the teeth are : — 



Length. Breadth. 



pm.4: 1-2 1-6 



m.l 1-6 1-8 



m.2 2-2 2-2 



m.3 2-5 2-5 



Length of molar series 5-8. 



M. 8425. Eight maxilla with pm. 3-4 and m. 1-3. The first and second molars are incomplete on 

 the outer side. Pm. 3 consists of a long trenchant outer cusp rising to a sharp point ; 

 internally the cingulum is well developed and forms a sort of shelf-like projection on 

 the postero-internal face of the tooth, which is therefore triangular in outline. This 

 tooth is borne on three roots, one beneath the anterior angle, the others arranged 

 transversely beneath the wider posterior portion. This tooth is shown in outline on 

 PI. XVIII. fig. 3. (pm. 3). The dimensions (in centimetres) of the teeth are : — 



Length. Breadth. 



pm.3 1-6 1-4 



pm.4: 1-4 1-7 



m.l 



TO. 2 2-2 app. 



m.3 2-6 



Length of molar series approximately 6'1 cm. 



M. 8423. Portion of palatal region of skull with pm. 3-4, m. 1-3 on the right side, and m. 3 on left. 

 The length of the molar series is 6 cm. 



* " Note on the Anthracotheriidse of the Isle of Wight," Geol. Mag. [3] vol. i. (1884) pp. 547-8. 



