Cope.] 214 [April 15, 



gradually to the inner rounded extremity. Viewed in profile it is strongly 

 convex, the convexity being a little nearer the internal than the external 

 extremity. The articular surface descends on the inner edge of the bone 

 towards but not to the bicipital crest. Viewed proximally, the convexity 

 of the head is as wide as the inner extremity, and is distinguished from it 

 by a concavity of the inner side. The bicipital crest is the incurved 

 external border. It commences opposite the prominence of the inner 

 extremity of the head, and extends but a short distance down the shaft. 

 It is quite prominent. The face of the bone below the head displays a 

 very shallow concavity. The posterior face is recurved towards the two 

 margins, as we approach them. The shaft is very much contracted. Its 

 section at the middle is a wide oval ; the external edge subacute, the 

 internal broadly rounded. The distal extremity is much expanded, 

 though not so widely as the proximal end. The expansion is greater 

 internally than externally. Neither epicondylar prominence, however, 

 extends much beyond the articular surface. The latter is rather narrow, 

 and is curved, the concavity anterior. The two extremities are wider 

 than the middle region, the external part being the widest. There is a 

 deep groove on the posterior face near the external edge, which runs out, 

 leaving the external epicondylar process to terminate at about 20 mm. 

 proximad of the condyle. The latter terminates outwards in an acute 

 angle, which marks the internal edge of the ectepicondylar groove. The 

 epitroclear fossa is well defined. Posterior face plane. 



Measurements of Immerus. M. 



Total length 230 



ilong (straight line) 088 

 r internal 025 

 transverse < greatest (submedian) 024 



i least (external) 015 



anteroposterior 021 



Diameters at middle of shaft , ^ ^„„ 



transverse 027 



( with ectepicondylar crest. .076 

 transverse I ^^^j^^ ,. .. q^^ 



Diameters of distal end \ e internal 021 



anteroposterior \ median 018 



(external 029 



The ulna is characterized by its small size, and its great compression, 

 especially of the distal half. The olecranon is deep, but it scarcely pro- 

 jects behind the cotylus, where it is more prominent than at the inferior 

 border. On the external side a regular convex mark extends from the 

 base of the corouoid process to the inferior posterior angle. Behind this 

 arc- like border, the surface of the bone is dense and smooth, as though 

 for a cartilaginous cap. "What this structure indicates it is difficult to 

 understand, as it is clearly not a muscular insertion. Tlie coronoid pro- 

 cess is quite prominent. The external face of the shaft is convex in the 



