276 C, H. HURST, PH.D. 



far as concerns the length of the ilium and its prolongation to about 

 an equal extent behind and in front of the acetabulum. If I mistake 

 not, it is conspicuously unlike the pelvis of any existing ' bird in the 

 matter of width, and the bearing of this will be shown in the sequel. 



The femur, more slender than in existing birds of the same size, is 

 strongly curved, the flexor surface being concave. 



The tibio-tarsus is almost perfectly straight, and has only a small 

 cnemial crest. The fibula is complete but slender. 



The foot is a characteristically avian foot. In the Berlin specimen 

 the matrix around the feet is so hard that a complete exposure of them 

 has proved impracticable. The London specimen shows the left foot 

 well. It is more massive and in every way larger than the corres- 

 ponding parts of the Berlin specimen. 



II. — The Feathers. 



The evidence before us does not justify the expression of any opinion 

 as to whether the body of Archceopteryx was covered with feathers all 

 over or only partially. Three chief kinds of feathers are, however, 

 recognisable in the fossils: — (1) quills, (2) coverts, and (3) contour 

 feathers. 



The quills are exceedingly well-preserved, especially in the Berlin 

 specimen. The remiges, or wing-quills, had the characters of those of 

 many ordinary birds, such as a pigeon. The calamus is not clearly 

 seen, as it is hidden by the coverts ; but the narrowing of the vane 

 near the base shows (e.g., in the second and third primary quills of 

 the left wing of the Berlin specimen) that its length was much the 

 same in proportion to the rest of the feather as in the corresponding 

 feathers of a pigeon. The rachis is clearly seen, and is slightly 

 curved so as to render the ventral surface of the wing concave and 

 the dorsal surface convex. It tapers gradually as in feathers of the 

 usual type. The groove seen along the dorsal surface of the rachis is 

 probably due to shrinkage of the medullary substance during fossilisa- 

 tion — but this point is open to dispute. The vane, as in nearly all 

 birds, is curved, the anterior and narrower moiety much more strongly 

 than the posterior, which latter is overlapped dorsally by the anterior 

 portion of the feather next following it. The barbs are easily seen, 

 even in photographs ; but I have been unable to make out the barbules 



