H.vrcHRR: Fork Limi; .wd M.anus of Bronto.saurus. 373 



The princi[)al dimensions of the phalanges found wiih this limb and 

 nianus are given in the following table, in which the measurements 

 given in columns i, 2, 3 and 4 show respectively the greatest length 

 and greatest breadth, and the greatest depth at the proximal and distal 

 e.xtremities of the different bones. 



position on the palmar side, lying between the distal end of rac. 

 III. and its pro.ximal phalanx. There is little doubt that digits II. 

 and IV. at least bore similar sesamoids in the same po- 

 sition, while others may have been interposed between ^^^^^ 

 some of the phalanges. It is not at all impossible that 



the small ossicles mentioned by Osborn and Granger as .' ''' .' 



•' ^ perior view 



found associated with other elements of the manus of of sesamoid 

 Diplodocus and referred by those authors to the carpus about one- 

 were in reality phalangeal sesamoids, as is evidently the fourth natural 

 case with the present ossicle. The maximum lateral di- ^'^^' (^o- 

 mension of this bone is 60 mm., 2.;8 inches, vertical 26 ^ 



mm., I inch ; while the fore and aft diameter exactly equals the vertical. 



Manus of Brontosaurus Entaxonic in Structure. 



From the above description and the accompanying figures it will 

 readily be seen that the manus of Brontosaurus, like the pes, was 

 entaxonic instead of inesaxonic as has been supposed by Osborn. 

 Digits II. and III. doubtless were provided with a full complement 

 of phalanges terminating in large unguals bearing powerful claws. In 

 digits IV. and V. the number of phalanges was doubtless successively 

 more and more diminished and the terminal of each reduced to a func- 

 tionless rounded ossicle similar to those found in the same positions 

 on digits IV. and V. of the pes in both Brontosaurus and Diplodocus. 



Xot only were digits I., II. and III. the only ones provided with a 

 full complement of phalanges, but the metacarpals decrease in strength 

 from the first to the fifth. The whole structure and arrangement of 

 the different elements of the metacarpus and phalanges is especially 



