BOIODONTID^. 203 



Dawkins, from the Upper Trias (Ehaetic) of Somerset ; and the 

 following form. There are, however, no characters by which the 

 two latter can be distinguished from the former, and their claim to 

 specific separation must therefore be regarded as provisional. The 

 structure of the teeth so closely resembles that of Bolodon^ that 

 there can be but little hesitation in placing both in the same family. 



Microlestes moorei, Owen \ 

 Hah. England. 



M. 2401. Three teeth ; from the Upper Triassic (Ehsetic) bone-bed 

 of Frome, Somersetshire. These specimens agree with 

 those figured by Owen in the memoir cited ; but the refer- 

 ence of the latter to upper and lower jaws is doubtful. 



By exchange ivith the Bath Institute, 1884. 



Genus BOLODON, Owen^ 

 Dentition : — I. ^-^, C. ~, Pm. |, M. ~. In the allied or identical 

 American AUodon, Marsh ^ regards the check-formula as Pm.|, M.| ; 

 but from No. 47735 a and the analogy of Tritylodon the above 

 formula is provisionally adopted. The upper premolars are conical 

 and have three cusps on their summit. 



Bolodon crassidens, Owen^ 



This is the type species. 

 Hab. England. 



The folloiuiny sjpecimens are from the Middle Purheck group of Dur- 

 dlestone Bay, Siuanage, Dorsetshire ; and belong to the Beckles 

 Collection. Purchased, 1876. 



47735. Part of the right maxilla, showing the second and third 

 {Fig.) incisors, premolars, and one true molar. This specimen 



is the tj^pe, and is figured by Owen in his ' British Meso- 

 zoic Mammalia ' (Mon. Pal. Soc), pi. iii. fig. 5. There is 

 a crack behind the second tooth which appears coincident 

 with the suture. 



47735 a. Part of the right maxilla, showing the three premolars and 

 tour true molars. This specimen, which was not seen 

 by Owen, has afibrded important evidence in determining 

 the homology of the teeth. 



47736. Fragment of the palate, showing two cheek-teeth on either 

 {Fig.) side. Figured by Owen, op. cit. pi. iii. fig. 6. 



^ 'British Mesozoic Mammalia' (Mon. Pal. Soc), p. 6 (1871). 



^ Ibid. p. 54 (1871). 



"'* Amer. Journ. ser. 3, vol. xxxiii. p. 329 (1887). * hoc. cit. 



