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University of California Publications. [Geology 



specimen, suggests the form of the basal region of a horn core 

 from Maragha, Persia, which has been considered by Weithofer 4 

 as possibly a young individual of Protragelaphus skouzesi. It is 

 not improbable that the Maragha form referred to may represent 

 a type distinct from Protragelaphus. 



The typical Ilingoceros differs from Prostrepsiceros in the 

 position and form of the spiral ridges, apparently also in the 

 sharper twist of the spiral, and in the wider space between the 

 bases of the horns. 



In Palaeoreas the anterior spiral ridge rises higher up on the 

 base of the horn than in Ilingoceros and is much nearer the 

 median line of the skull, so that the general aspect of the horn 

 is quite different from all points of view. 



The specimens included in the genus Spenophalos resemble 

 Ilingoceros and the tragelaphine division of the antelopes in 

 the absence of cavities at the base of the horn cores, as also in 

 the density of the horn core as a whole. In the specimens 

 available the horns are much flattened laterally, and have evi- 

 dently not developed a series of spiral ridges like those of 

 Ilingoceros, or the typical strepsicerine forms. The nature of 

 the frontal region does not differ greatly from that of Ilingoceros. 



Sphcnophalos resembles the existing prong-horn antelopes 

 somewhat in the general form of the horn core, and probably 

 also in the character of the surface of the core. The horn cores 

 of Sphcnophalos differ from those of Antilocapra in their rela- 

 tively greater thickness, and in their more oblique position with 

 reference to the long axis of the skull. They also occupy a 

 slightly more posterior position with reference to the orbit and 

 are directed backward, instead of standing erect as in Antilo- 

 capra. The posterior side of the base of the horn core in 

 Sphcnophalos presents a broad, Hat, gently-curving surface, 

 entirely different from the narrow, prominent posterior edge of 

 the base of the horn core in the prong-horn. There is also a 

 noticeable difference in the slope of the roof of the skull behind 

 the horns, this region dropping away from the plane of the fore- 

 head more sharply in Sphcnophalos than in Antilocapra. 



* Weithofer, K. A., Denksch. d. k. Acad. d. Wiss. Math. Naturwiss. CI.. 

 Bd. 57, Taf. 5, Fig. 2. 



