424 E. S, GOODRICH. 



marsupial and nearly related to Thylacinus; Amphitherium, 

 on the other hand, he places nearer the Insectivora, and in 

 one work (20) puts it actually iu that group. Lydekker classes 

 all these Stonesfield Mammalia in one family, the Amphithe- 

 riidae (including Amblotherium, Achyrodon, and Peramus) ; 

 but there can be no doubt that Amphitherium should be widely 

 separated from the tricouodont group (Phascolotherium and 

 Amphilestes). Osborn includes the latter with Triconodon 

 and its allies in one group, the Triconodouta ; Amphitherium 

 he places with the living Polyprotodont Marsupials in the 

 group Trituberculata, which also includes Amblotherium and 

 its allies. Zittel adopts this arrangement, which certainly 

 seems to be the best and safest yet proposed. 



Stereognathus ooliticus, Charlesworth. 



The only specimen of this interesting Multituberculate 

 form has been purchased for the Museum of Practical Geology 

 (London), where it now rests. This fossil, a fragment of a 

 jaw containing three molars, came from the collection of the 

 Eev. J. Dennis, of Bury, and was originally described by 

 Charlesworth ia 1854 (6a) as a piece of the lower jaw with 

 molars having " six similar cusps arranged in two rows " 

 (transverse). Three years later Owen described and figured 

 Stereognathus in detail (21a). The teeth, with their three 

 longitudinal rows of two cusps, he considers somewhat re- 

 sembled those of certain Uugulata, concluding that they 

 belonged to a " diminutive form of the great Ungulate order 

 of Mammalia." Marsh (12a) suggested that the fossil belongs 

 to the upper jaw, as no Multituberculate teeth of the lower 

 series are known to possess more than two longitudinal rows 

 of cusps. The specimen is, however, too fragmentary to 

 enable us to come to any definite opinion on this point ; and 

 its exact systematic position, therefore, must remain some- 

 what uncertain. It is generally classified in the family 

 Plagiaulacidse (14, 32).i 



[} I take the opportunity of Mr. Goodrich's publication to record once 

 again the existence of another Stouesfield jaw, which I obtained from a 



