256 O. C. Marsh — Discovery of Cretaceous Mammalia. 



The lower teeth of the present genus are not known with 

 certainty. The specimens here figured are from the Laramie 

 of Wyoming. 



Allacodon rarus, sp. now 



Among the specimens above described a few isolated teeth 

 were found, one of which is represented in Plate YII, figure 5, 

 and may be provisionally referred to the genus Allacodon. It is 

 a molar tooth, with four rounded tubercles on the crown, yet 

 these are not crowded together as in the known species of this 

 genus, but the anterior and posterior pairs are separated by a 

 deep transverse groove, showing a distinct type of tooth. This 

 is well shown in the figures given. Additional specimens must 

 determine its nearer affinities. 



Oracodon conulus, sp. nov. 



The teeth of this genus have well marked characters, but 

 none have yet been found in position, or so associated with 

 other remains as to afford any evidence of where they really 

 belong. Although their general features are distinctive, there 

 are various forms and sizes among those now known. The 

 two teeth shown on Plate YII, figures 6 and 7, agree sub- 

 stantially with the type specimen of Oracodon anceps, described 

 in Part II. A somewhat larger form, represented in Plate YII, 

 figure 8, appears to be different, and is taken as the type of the 

 species here regarded as new. Its important characters are 

 well shown in the figure. 



The teeth figured appear to be upper premolars, and one of 

 them shows a worn surface on the inner side of the crown. 

 They are here placed with the Allotheria, and a fortunate 

 discovery may at any time prove their proper position among 

 the varied remains of this group. 



The Stagodontidm. 



A large number of specimens belonging to this family have 

 been discovered since the first were described. These are quite 

 distinct from any other remains from this horizon, and several 

 of them are figured on Plate YIII, with the type specimens of 

 the two species of iStagodon previously made known. Some 

 of the new fossils indicate the largest mammal yet found in 

 the Laramie, and this is described below. 



Stagodon validus, sp. nov. 



The type of the present species is the anterior portion of a 

 right lower jaw represented on Plate YIII, figure 7. This 

 shows alveoles for three incisors closely crowded together, the 



