31 



The species exhibits a great amount of variation in cranial characters, 

 even in the same sex. In the normal form (fig. 3, A) the horn- 

 cores of the males are triangular, with a sharp ridge anteriorly ; in 

 the trochoceros form (fig. 3, B) they have a pear-shaped section, and 

 recede very rapidly from the forehead; in the third or aepoceros 

 form (fig. 3, D) they are more upright ; whilst in a fourth (fig. 3, C) 

 the horns are entirely wanting. A large series of crania are figured 

 by Eiitimeyer in the ' Einder der Tertiar-Epoche ' (Abh. schweiz. 

 pal. Ges. vols. iv. and v. [1877-1878]), and by the present writer 

 in the ' Palseontologia Indica,' ser. 10, vol. i. pis. xx. to xxiv. 

 Hob. India. 



All the following specimens are from the Pliocene of the Siwalik 

 Hills, and, unless otherwise stated, belong to the Cauiley Collection, 

 Presented, 1842: 



16411. The greater part of the cranium of a male of the normal 

 (Fig.} form, with part of the right horn-core, which has a tri- 

 angular cross section. This specimen is noticed by Eiiti- 

 meyer in the ' Einder der Tertiar-Epoche,' p. 127, and is 

 figured by Falconer and Cautley in the ' Fauna Antiqua 

 Sivalensis ' (unpublished) plate H. figs. 2, 2a. 



39565. The cranium of a male of the normal form, with the base 

 (Fig.} of the right horn-core. This specimen is described and 



figured by Eiitimeyer, op. cit. p. 122, pi. vii. figs. 1, 2 (as 



No. 39563). 



23109. Lower portion of the cranium of a male. This specimen is 



(Fig.} described and figured by Eiitimeyer, op. cit. p. 127, pi. iv. 



figs. 1, 2. Presented by Col. Colvin. 



36665. Part of the calvarium of a male of the trochoceros form. 



(Fig.} This specimen is described and figured by Eiitimeyer, 

 op. cit. p. 129, pi. i. figs. 3, 4. The horn-cores have a 

 pyriform section ; and the specimen agrees very closely 

 with the more perfect skull, which is the type of Fal- 

 coner's Bos occipitalis, figured by the present writer in the 

 ' Pala3ontologia Indica,' ser. 10, vol. i. pi. xx. 



48031. Calvarium and part of the horn-cores of a male of the 

 (Fig.} trochoceros form. This specimen is described and figured 

 by Eiitimeyer, op. cit. p. 131, pi. vi. fig. 11. 



48028. Calvarium and the base of the right horn-core of a male of 

 the trochoceros form. Noticed by Eiitimeyer, op. cit. 

 p. 129. Presented by Dr. H. Falconer. 



