ANCODON GORRINGEI. 
181 
M. 8424. Paliital region of skull with teeth. On the right side pm. 4 and »?. l-?t are preserved, on 
the left ?«. 8 is wanting. Right side figured PI. XVllI. fig. 8. In the figure pm.‘.\ is 
drawn in outline from another s])ecimen (M. 8425). 
The fourth premolar consists of an outer crescentic cusp and a large inner rouiuhal 
tubercle ; the cingulum is well developed on the inner side. This tooth resembles th<^ 
fourth ))remolar of the other species of Ancodon and differs from that of Jiracltj/odu.s in 
the al>sence 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 tlui 
family are composed of five main cus})s, three anterior and two posterior. These cusps 
are lower and much less distinctly selenodont than in the other s{)ecies of Ancodon 
except .^1. porcinus, Gerv., a species which Lydekker * has shown to be intermediate in 
molar structure between the typical species of A7icodon and Anthracothenuni. Tin; 
outer wall is strongly folded into a W-shaped ectoloph, the parastyle and mcsostyhi 
being very prominent in all the molars, while in m. 8 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. por'cinus and in Braclujodus, while in 
the more hypsodont species of Ancodoji the cingulum is almost wanting on the inner 
side of the teeth, and in Antliracotherium 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 . 1 1'6 1‘8 
m.2 2-2 2-2 
W.3 2-5 2-5 
Length of molar series 5'8. 
M. 8425. Right maxilla with jam. 3-4 and m. 1-3. The first and second molars are incomplete on 
the outer side. Pm. 8 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 
n. XVIII. fig. 3. {pm. 8), The dimensions (in centimetres) of the teeth are : — 
Length. Breadth. 
pm. 3 1'6 1'4 
pm. 4 1-4 1-7 
m. 1 
m. 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 AnthracotheriidiJe of the Isle of Wight,” Geol. Mag. [3] vol. i. (1884) pp. 547-8. 
