386 MESSES. HANCOCK AND ATTHEY ON A 



part of that gentleman's well-known collection, and is from 

 the new ironstone shale of Fenton. It is a portion of the pos- 

 terior extremity; but the articular process is wanting. The 

 fragment is seven inches long, and measures nearly four inches 

 from the alveolar border (PI. XII. a) to the inferior margin (b). 

 There is just two inches of this margin perfect ; and this is at 

 the point where undoubtedly the ramus is deepest. The inner 

 surface is exposed to view, and is concave longitudinally, the 

 outer surface being a little convex, as is evident in the trans- 

 verse section of the specimen in front. The bone, which is in a 

 very perfect state of preservation, is composed of two parallel 

 layers — an inner, the splenial plate (c), and an outer, the den- 

 tary piece (d) — and is stout, particularly at the alveolar border, 

 where it is an inch thick ; thence it becomes gradually thinner 

 to the longitudinal middle line ; here it is scarcely more than 

 one-fourth of an inch thick, and so continues to the inferior 

 margin. 



The upper surface of the alveolar border is slightly channelled, 

 and is almost straight ; but within three inches and a quarter of 

 the posterior extremity it is bent a little downwards (e), and 

 then, rising up considerably above the level of the border, is 

 continued backwards in a straight line (/) to the posterior ex- 

 tremity ; this straight part is one inch and a half long, and is 

 bevelled off to a sharp edge. In front of the elevation the al- 

 veolar border has been torn, apparently by pressure, from the 

 inner layer of bone, which at this part is pushed a little down- 

 wards. 



The teeth are well preserved ; in all there have been twelve, 

 nine of which are almost perfect, and with the exception of the 

 three posterior ones, are all of the same size. They are nearly 

 an inch long, and at the base are upwards of a quarter of an 

 inch wide ; they taper gradually to the apex, which is a little 

 compressed in the direction of the long axis of the jaw, and in 

 the same plane has the sides slightly carinated, and is also rather 

 suddenly bent inwards and backwards ; but the recurving is 

 probably, in part at least, owing to pressure. The crown is not 

 perfectly cylindrical, or rather conical ; it is a little flattened at 



