NO. 1666. OSTEOLOGY OF CAMPTOBAURUS—GILMORE. 275 



The iDi-eacetabiilar process of this particnhir individual is un- 

 known, and in the first figure of this element it was represented as 

 being a very short, blunt process (see fig. 8(5). As previous!}^ stated, 

 the first figures given are now known to be erroneous. 



The shaft of the ischium of C. dispar is more robust, and at its dis- 

 tal termination has a larger hanmier-like development of this end 

 than is found in any of the known species (compare is, Plates 15 and 

 16), the greatest diameter being 100 mm. The pubis does not show 

 any especial differences, while the post-pubis is almost wholly 

 restored. 



The limb and foot bones do not exhibit any especial characters 

 except a more robust development than is found in the smaller spe- 

 cies. It is at once distinguished from C. ampins by the greater size 

 and the comj^ressed, sauropod-like ungual of Digit I of the latter, 

 as compared with the rounded, claw-like element of C. dispar (com- 

 pare fig. 35 Avith fig. 38 and Plate 17). 



Of the pes of No. 1877 I need mention only the extreme shortness 

 of Metacarpal I as figured by Marsh. When compared with com- 

 plete elements it appears that the upper third is missing, which 

 would account for the extreme brevity of this digit as originally 

 figured. In the same cut Digit III is represented as bearing the 

 heaviest ungual, when, as shown by the pes of Cat. No. 4277,U.S.N.M. 

 (see fig. 35), Digit II carries the most robust terminal phalanx of the 

 hind foot. A cast of the foot in question now before me shows an 

 ungual attached to the second digit whose small articular surface in- 

 dicates at once that it has been wrongly placed, and in all probability 

 pertains to Digit IV. 



The manus, if correctly associated with the pes just discussed as 

 pertaining to the same individual, shows variation from the same 

 elements in Cat. No. 5473, U.S.N.M., being much lighter in construc- 

 tion, the hind feet having about the same dimensions. The associa- 

 tion of the fore and hind feet of this latter individual is undoubtedly 

 correct. 



The fifth metacarpal is unusually short. The ungual of Digit III 

 is very small, weak, and sharply pointed. Carpale five, as shown in 

 the earlier figures of the manus of O. dispar, contributes to the articu- 

 lating surface for the ulna and is so shown in the cast of the right 

 fore foot. The unusual position of this element would hardly point 

 to the true interpretation of the proper articulation of these bones, 

 and it has been depicted otherAvise, as shoAvn in fig. 28. In the 

 right foot I can only recognize seven carpal elements, although the 

 eighth is probably fused with the radiale and Metacarpal I, and has 

 thus lost its identity. Carpale three is almost wholly articulated Avith 

 the proximal end of Metacarpal III. It is Avedge-shaped, the thick- 

 ened part being posterior. Carpale Iavo occupies a posterior position 



