MARYLAND GEOLOGICAL SURVEY 167 



defined species. The markedly large size of the California specimens cer- 

 tainly implies the specific or sub-specific rank of the animals, unless, as 

 suggested elsewhere, they should prove to belong to E. imperator, a point 

 that will only be settled by the discovery of a jaw. 



Eastern teeth, even those from Florida, average smaller than those 

 from the Southwest. Maryland examples are of the smaller size, but 

 the tooth-ridge formula is entirely characteristic. 



This species is represented in the collections of the Maryland Geologi- 

 cal Survey by three specimens, but one of these is so evidently from 

 Florida that it will not be considered here. Another specimen ascribed 

 to E. colurribi is one of the intermediate forms that have been referred 

 to as making it very difficult to identify the species of elephants from 

 individual teeth. While from the number of enamel ridges it would just 

 come within the definition of E. primigenius, as there are 20 enamel 

 plates in a distance of 9^ inches, yet in its general appearance the width 

 between the sides of the enamel pockets and thickness of enamel itself, 

 the tooth resembles that of E. colurribi and is referred to that species. 

 It comes from Oxford Neck within a mile of the large tooth of E. primi- 

 genius, with which it compares very well, not only in point of size, but 

 in general condition. The third example is a small, somewhat worn 

 typical tooth of Elephas columbi of particular interest from being of the 

 same size and general character as a tooth of E. primigenius also in the 

 collection, the two being excellent for purposes of comparison. The tooth 

 measures 5^ inches in length by 3 in width and bears 9 enamel folds, or 

 strictly speaking, 9-J, as this is one of the occasional teeth in which a 

 single fold occurs intercalated between two complete loops. 



Collections. — Maryland Geological Survey, U. S. National Museum 

 and American Museum of Natural History. 



Elephas imperator Leidy. 



THE IMPERIAL MAMMOTH. 



Plate XXXVIII, Fig. 2 ; Plate XXXIX, Fig. 3. 

 Elephas imperator Leidy, 1858. Proc. Acad. Nat. Sci. Phila., p. 10. 



Description.— Jaw extremely massive, each ramus being so short, 



