Cope.] 4d4. [May 3, 



but one molar each of H. occidentale and FT. sinrAairU, both from Cotton- 

 wood creek, Oregon, n. speciosum is the most abundant and widely dis- 

 tributed species ; Leidy reporting it from Dakota, Nebraska and Texas, 

 and its occurrence in New Mexico being recorded in my report to Lieut. 

 Wheeler. Mr. Hill has since obtained fine specimens in Kansas. The 77. 

 paniense is known from a few teeth obtained by myself in Northeastern 

 Colorado. The 11. calamarium I found to be the predominating species 

 in the Loup Fork beds near Santa Fe, New Mexico, and it is not rare in 

 Northeastern Colorado. H. isonesum was apparently common in the 

 Northwest, two fine specimens having been found by ]\Ir. Wortman on 

 the Cottonwood creek, Oregon, and one or more on the Deep river, Mon- 

 tana, by Mr. J. C. Isaac. H. .teversum is so far only known from an Ore- 

 gon specimen. The If. relictam has been so far also only found in 

 Oregon. 



HlPPOTHEUIUM OCCIDENTALE Lcidy. 



Proceed. Academy Philada., 1858, 27. Hippnrion occidentale Leidy, Pro- 

 ceed. Academy Phila., 1856, 59. Extinct Mammalia Dakota Nebraska, 

 1869, 281, 326, PI. xviii. Figs. 1-5 ; xxvii, Fig. 2. 



Known to me from a single superior molar tooth of the left side, fcmnd 

 by Mr. Wortman on Cottonwood creek in Eastern Oregon. 



The crown is very long, and almost rootless, and the cement layer is 

 quite thick, especially towards the distal portion of the crown. The inner 

 anterior column is flattened, and occupies a middle part of the fore and 

 aft diameter of the crown. It is sliglitly crescentoid in section, and pre- 

 sents its anterior apex slightly inwards. Tlie posterior inner lobe is not 

 cut off from tiie inner crescent by any contraction. Tlie lakes have their 

 inner portions very prominent and marked off from the external portiim 

 by deep inflections of the border. There are two posterior and two inte- 

 rior inflections of the anterior crescent, and the adjacent ones of the two 

 pairs nearly cut oflf a lar^^e loop, which thus occupies the centre of the 

 crown. The posterior lake has two anterior and no interior inflections. 



Meaanrements. 



M. 



Length of crown 056 



j anteroposterior 024 



1 transverse 



Diameters of crown 



.024 



I suspect that the lUppotherium nffine'LG'u\y (Extinct Mammalia, Dakota 

 and Nebraska, p. 286) is based on young individuals or represents a slight 

 variety of this species. 



HiPPOTHERiUM srNCLAiRii Wortman. 



Pevue Scientifique, Paris, 1883, p. 712. 



I know a single left superior molar of this species. It is easily distin- 

 guished from the corresponding tooth of U. occidentale by its inferior size 



