i8 95 . THE STRUCTURE OF ARCH&OPTERYX. 117 



humerus which is slightly shorter than the true length. It unfortu- 

 nately has given rise to the supposition that I "retouched" the 

 photograph before sending it for reproduction — which, of course, is 

 not true. 



The bones of the fore-arm seen in the plate facing p. 275 of 

 vol. iii., and on p. 351 of vol. v., and in Plate I. herewith, are a 

 straight radius 55 mm. long, and a curved ulna 56 mm. long. 



The carpus offers great difficulties. Owen figures two bones, 

 one of which is visible in the London specimen. Why he should 

 ignore the enormous ulnar carpal, which is a conspicuous object in 

 the London specimen, need not here be discussed, as I am not now 

 discussing the origin of errors. It is conspicuously shown in fig. 2 

 and in plate i. of Owen's memoir, where it is numbered 56' and 

 described (presumably with the radial carpal) as " left carpus " (it 

 being of course a part of the right carpus), and something wholly 

 unlike it is put in its place, in dotted lines, in his second plate in the 

 figure which is reproduced as Fig. 2 (p. 439) of Mr. Pycraft's paper in 

 the last volume of this Journal. 



Of these bones I have seen two clearly, one being the radiale (4 

 in Plate J.), which is visible in both the specimens, the other the 

 " ulnare," visible only in the London specimen. In the Berlin 

 specimen the carpus lies radial side uppermost, and it is not surprising 

 that, like some other parts, the ulnar portion of the carpus lies still 

 embedded in the matrix. This is even admitted by Dames. The 

 little bone called "ulnare" and drawn from imagination by Owen, 

 and also drawn by Dames, may or may not be present. I have tried, 

 and failed, to make it out in the Berlin specimen, and I have also 

 tried, and failed, to make sure that it is not there. One thing only I 

 can say of it, viz., if present it is probably the intermedium, and not 

 the ulnare. The " ulnare " is the enormous and conspicuous bone 

 shown at the distal end of the right radius and ulna in Fig. 2. It is, 

 for a carpal bone, of enormous size, and I am not prepared to believe 

 that it played no part in the support of the metacarpals. 



Of the distal row of carpals it is only possible to say that they 

 are not yet recognised in either specimen. Whether they have fused 

 with the metacarpals, as they do in modern birds, or were cartilaginous 

 and so not preserved, or were fused with the bones I have referred to 

 as belonging to the proximal row ; or whether the two figured by Owen 

 and Dames are the proximal row, and the large bone I have called 

 " ulnare " is really, as the London specimen suggests, a fused mass 

 representing the whole distal row of carpals, can only be decided, so 

 far as I can see, by one of two consummations " devoutly to be 

 wished" — (1) the excavation of the exceedingly thin and fragile 

 Berlin slab from the back, or (2) the discovery of fresh specimens.. 

 The first of these involves too great a risk to what it is hardly an 

 exaggeration to say is the most valuable palaeontological specimen in 

 any museum in the world. 



