Vol. 6] Merriam: Virgin Valley and Thousand Creek. 



301 



sand Creek from which all of the twisted-horned forms were 

 derived. All of the larger Virgin Valley specimens representing 

 antelope-like forms are to be referred to Dromomeryx (Palaeo- 

 meryx.) 



Some of the hypsodont molars from Thousand Creek pre- 

 sumably represent the forms included in the genus Sphenophalos, 

 but one seems hardly justified in referring all of the specimens 

 to that genus, inasmuch as not more than a third of the total 

 number of skull fragments obtained belong to Sphenophalos, and 

 in two instances horn-cores representing the twisted form were 

 found in fairly close association with the long-crowned molars, 

 while remains of Sphenophalos were absent. 



It appears most reasonable to consider the probabilities in 

 favor of associating some of the long-crowned molars with the 

 skull fragments bearing twisted horns. Some of these teeth, as 

 has been shown under the discussion of Sphenophalos, are evi- 

 dently near the Antilocapra type, and none of them, so far as 

 known, seem to differ greatly from those of that form. It is also 

 true that such skeletal remains as are known seem to differ little 

 in general character from the type of Antilocapra. Unfortu- 

 nately, excepting the skulls, no skeletal parts of the tragelaphine 

 antelopes are available to the writer for comparison with that 

 group. 



The indirect evidence of relationship suggested by the den- 

 tition indicates that the twisted-horned forms are related to 

 Sphenophalos and, with that genus, to Antilocapra. The pre- 

 sumable relationship of Sphenophalos to Antilocapra has already 

 been discussed. It seems, however, certain that Ilingoceros is 

 generically quite distinct from Sphenophalos and, whatever the 

 grade of relationship, Ilingoceros seems farther from Antilo- 

 capra than is Sphenophalos. 



With the scanty evidence available, the characters in which 

 Ilingoceros seems most distinctly connected with Antilocapra 

 are the presumptive similarity in the dentition and the nature 

 of the outer portion of the horn-core, which like that of Spheno- 

 phalos seems to be a little more dense than is common in the 

 tragelaphine forms. Otherwise it is hard to find characters 

 which are distinctively antilocaprine. 



