1913] 



Merriam: A Peculiar Horn or Antler 



337 



is projected approximately in the plane of the flattened beam. 

 The other branch curves rather sharply away from this plane. 

 (See fig. 2). The branch bending away from the plane of the 

 beam is the smaller. A number of the superior spikes or papillae 

 bend out at a low angle from the convex side of the curve formed 

 by the two branches. It seems probable that the plane of the 

 beam was anteroposterior rather than transverse to the skull, 

 and that the papillae on the convex side of the bow are on the 

 outer or lateral, rather than on the inner side of the horn. If 

 the smaller of these two horizontal branches is the anterior, this 

 is the right horn. 



The spikes or papillae on the upper side of the horn are in 

 two rows. There are six on the concave side, and four on the 

 convex side. The inner six are arranged in three pairs. Of the 

 outer four there is a single large spike opposite the posterior 

 inner pair and a similar one opposite the space between the 

 anterior and middle inner pairs, and a pair of papillae arising 

 from a common base opposite the middle inner pair. The inner 

 papillae are nearly erect excepting the most anterior one. The 

 papillae on the outer side are directed outward at a low angle. 



Judging from the single specimen available, the anterior 

 branches of the right and left horns of this animal curved in 

 toward each other over the face, the other branch extended back- 

 ward and slightly inward, making a crown-like or horseshoe-like 

 structure above the head. One row of the small spikes or 

 papillae was directed upward, and the other row was directed 

 outward around the margin of the crown. 



Specimen 20052 most nearly resembles the horn or antler of 

 Merycodus, which it also approaches in size, and to some extent 

 in the texture of the horn. It differs from Merycodus in the 

 form of branching, and in the presence of the double row of 

 superior spikes. The texture of the surface of specimen 20052 

 differs somewhat from that of any of the numerous Merycodus 

 horns available from the Mohave Miocene. In no. 20052 the 

 surface is marked by numerous wavy reticulating lines or ridges, 

 which are not matched exactly on any available Merycodus speci- 

 men. It is possible that the contrast is due in part to condition 

 of weathering, but it seems partly due to difference in structure. 



