Char, specif. Size very small. The molars, except the first, with a 

 distinct but narrow posterior third column, their sides grooved nearly 

 to the centre. Incisor sub-triangular in section. 



Measurements. 



M. 



Length of anterior three molars 0066 



" first molar 0024 



Width " " 0018 



Depth ramus at first molar 0060 



Other specimens are a little smaller than the above. 



Tricitjm leporinum, sp. nov. 

 This species is larger than the last, and the molars lack the posterior 

 column which it possesses. The first molar is narrowed in front, and is 

 not grooved to the base on either side ; the second is grooved to the 

 alveolar wall on the inner side only, the others on both sides. 



Measurements. 



M. 



Length of anterior three molars 0076 



" first molar 0025 



Width " " 0020 



Depth of ramus at first molar 0070 



Tritium agapetilla is allied to this species ; I originally referred it to 

 Palceolagus (see Bulletin No. 15). 



Tricium paniense, sp. nov. 

 This species is similar in the dentition of the anterior part of the jaw 

 to the last species, but is quite distinctly larger, as the following measure- 

 ments explain. The region of the diastema is quite stout, and the 

 incisor convex on the anterior face. 



Measurements. 



M. 



Length of two anterior molars 0068 



" first molar 0032 



Width " " 0021 



Depth ramus at first molar 0085 



" " diastema 0061 



Gtmnoptychus chrysodon. Gen. et sp. nov. 



Char. gen. The essential features are, dentition ; I. \ ; C. % ; M. f ; 

 the molars with two crescents on the inner side above, each of which 

 gives rise to a cross-ridge to the outer margin. In the mandibular 

 series the crests and crescents have a reversed relation. No cementum. 



Char, specif. First upper molar a single cone. Incisors, quite com- 

 pressed. First inferior molar a broad oblong, the cusps opposite, the 

 anterior close together. The two posterior cross crests do not form a V, 

 the anterior being interrupted at the cusp. There is a delicate tubercle 



