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THE AMERICAN NATURALIST [Vol. XLI 



the specimen, but it continues from the inion to the orbital bor- 

 der. The orbit is located well forward on the skull and is open 

 posteriorly in a similar manner to that of the known pAiropean 

 forms. The maxillary bone is high and the maxillo-prem axillary 

 suture ascends rapidly. The premaxillary bone of Moropus is not 

 known, but I judge that it attained a considerable length and was 

 perhaps edentulous or retained small incisors.^ The infra-orbital 

 foramen is large and is placed above D*. The jugal is small with a 

 delicate zygomatic process. The zygomatic process of the squamo- 

 sal is equally small so that the arch is rather more delicate' than 

 that represented in the European genus. The glenoid process is 

 of fairly large size and the space between the latter ])r()cess and 



the paroccipital is occupied bv the external ear and the mastoid in 

 much the same way as in the recent horse. The external auditory 

 meatus is of fairly large size and is directed outward and very 

 sliglitly upward, not unlike that in Equus. Whether or not there 

 was a tympanic l)nlla cannot be determined from the material at 

 hand. The occipital condyle is large and there is a slight acces- 

 sory facet on the basioccipital. The condylar foramen is of large 

 size and is situated innnediately back of the paroccipital process at 

 its internal angle. The latter process is much elongated and sug- 

 gests that of the recent horse. Tn fact a number of osteological 

 features of Moropu. .u--, .t < Imku t( r. in the r(,iiinc fainilv of the 

 Perissodactyhi. 



