M(ERITHERirM LTONSI. 



121 



fig. 2 c ; also PI. X. fig. 1. The vertebra is figured on PI. XI. fig. 4. Middle Eocene. 

 The dimensions (in centimetres) of the mandible and lower teeth are : — 



Total length 32 



Height of condyle above inferior border ........ 15'3 



Length of molar and premolar series 17"2 



pm. 2 



pm. 3 



pm. 4 



m. 1 



TO. 2 



m. 3 



U. 8146. Plaster cast of the above specimen. 



Made in the British Museum. 



C. 7867. Nearly complete skull of a young individual in which the second incisor and last molar 

 are not yet cut. The description of the skull given in this volume is founded mainly 

 upon this specimen, which is figured on PI. VIII. and PI. IX. fig. 1. Upper Eocene. 

 The approximate dimensions (in centimetres) of this skull are : — 



Greatest length' from end of condyles to tip of snout ... 35 



Length from hinder border of palate to tip of snout .... 21 



„ summit of occiput to tip of snout 32 



Greatest width at zygomatic processes of squamosal .... 22-7 



„ of occipital surface 17'4 



,, of supraoccipital escutcheon 9'7 



Height of occipital surface above foramen magnum .... 8'7 



"Width between outer angles of condyles 9'3 



of sknll-roof at temporal fossa 6 



„ orbits 6'6 



of glenoid surface 7'3 



of palate between m. 1 3*3 



of foramen magnum 4*2 



Length of premolar series 7"3 



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



^m. 2 

 pm. 3 

 pm. 4 

 m. 1 

 ni, 2 



Length. 

 2-7 

 2-5 

 2-1 

 3 

 3-2 



Width. 



2 



2-8 



2-8 



2-6 



2-9 



M. 8875. 

 M. 9225. 



Made in the British Museum. 



Plaster cast of the above specimen. 



Skull, very slightly crushed and nearly complete^ with the exception of the zygomatic 

 arches : the nasals are well preserved and terminate anteriorly in points which overhang 

 the narial opening. The vertical plates of the pterygoids are thick and appear to have 

 a descending plate of the alisphenoid fused on their outer face ; there is an alisphenoid 

 canal opening anteriorly into a groove running upwards and forwards, as in Palceo- 



R 



