488 PROCEEDINGS OF THE ACADEMY OF [1897. 



A conservative estimate of the original length of the horn-core, add- 

 ing two inches (50 mm.) to the broken apical portion and two more 

 for the basal part, makes it 800 mm. when measured along its pos- 

 terior arc on a plane with the occiput ; the same measurement in No. 

 13,754 is only 520 mm. The girth of core of crampianus measured half 

 way from base to tip, where the specimen is best preserved, is 305 

 mm., while that of No. 13,754 is 241 mm. These dimensions show that 

 in crampianus we have a species bearing horns more than i heavier 

 and longer than the large-horned Alaskan animal, and in this respect 

 showing a difference out of all proportion to the greatest known dif- 

 ference shown by adult males and females of the same species in exist- 

 ing bisons. Examining next the shape of the horns in the specimens 

 under consideration we note a striking difference, quite sufficient 

 when present in living species, to denote specific values. The greatest 

 diameter of the horn-core of cramp ianus, measured at a point half way 

 between base and tip, is 105 mm., the least diameter 92 mm., the first 

 of these measurements being taken along a line parallel to the facial 

 plane and the second at right angles thereto. In No. 13,754 these 

 measurements are respectively 88 mm. and 67 mm., showing the 

 greater superior flatness of the horns of the Alaskan animal. A 

 median cross-section of the core of crampianus, in the words of it& 

 describer, " is a triangle, with a broadly rounded apex." It is more 

 properly a truncated oval or ellipse, the flattened or hollowed 

 truncate portion corresponding with the posterior face of the core. 

 In No. 13,754 the same section presents a rounded hemispheric out- 

 line, the flat side of which is on a line with the facial plane and 

 forms the superior anterior face of the core, and the truncated side 

 seen in crampianus, is replaced by a convex, rounded curve, falling 

 posteriorly into a. larger one and terminating anteriorly quite 

 abruptly along the superior posterior edge, which forms a distinct 

 ridge at this part along the distal half of core. 



The relations of No. 13,754 to crampianus being now made appar- 

 ent, it should be stated that the author considers the latter a syno- 

 nym of B. alleni Marsh, briefly described in the American Journal 

 of Science, 8 from a single horn core " from the lower Pliocene of 

 Kansas." The dimensions and curvature of this specimen, together 

 with the locality and geologic stratum from which it was taken, 

 duplicate too closely the characters and history of the crampianus 

 type to warrant any other conclusion, and the foregoing remarks 



8 Am. Jour. Sci., 1877, No. LXXXI, p. 252, Appx. 



