STRUCTURE AND HABITS OP ARCHJEOPTERYX. 277 



with certainty. Their existence, and even that of the hooks which 

 serve to maintain the relative positions of the barbs, is safely to be 

 inferred from the perfect regularity with which the barbs lie side by 

 side in the Berlin specimen. 



Of the quills, there are in each wing seven primary and ten 

 secondary. The lengths of the primary quills, i.e., of the quills borne 

 by the metacarpals and phalanges, are as follows (commencing with 

 the first) :— 65, 90, 120, 125, 135, 130, and 120 mm. The secondary 

 quills, borne by the ulna, are not easy to measure accurately, but they 

 diminish gradually from the carpal region to the elbow. The first is 

 115 mm. long; the last or tenth, 75 mm. Taken as a whole, these 

 remiges, though less numerous than in most modern birds, are as 

 perfectly fitted, by their form and arrangement, for the purpose of 

 flight as in, say, a pigeon. Their size, though not difficult to deter- 

 mine absolutely, is difficult, if not impossible to determine relatively 

 to the weight of the body ; for in our guesses at the weight of the 

 animal a very large margin must be left for possible error. 



The rectrices, or tail quills, differ very remarkably from those of any 

 other known bird. Unfortunately, I overlooked the question as to 

 their number when I was in Berlin. Previous authorities regard 

 them as arranged in pairs, one pair to each vertebra of the tail, but 

 Dames is very cautious on this point. My large photographs suggest 

 that they are somewhat more numerous, but the point is one which 

 may be left for the present undetermined. They differ from the cor- 

 responding feathers of modern birds of flight chiefly in size, being very 

 much smaller than those of ordinary birds of equal size. Those of the 

 anterior part of the tail are about 50 mm. long, or perhaps a little less 

 (Berlin specimen). Further back they are longer, the maximum 

 length of about 95 mm. being at about the twelfth caudal vertebra. 

 To what extent, if any, they could be spread out and closed together 

 we can only guess, and the fact that they lie in both specimens at an 

 angle of about 30° to the axis of the tail does not help us much; for 

 if the animal had the power of spreading its tail-feathers, this would 

 perhaps have been effected by means of a muscle arising from some 

 bone in the pelvic region, through the mediation of a slender tendinous 

 band running along each side of the vertebral column of the tail, and 

 opposed by a slender elastic ligament which would, when the muscle 



