264 NATURAL SCIENCE. April, 



under some of these feathers, and so has raised the free or "distal" 

 edges distinctly above the level of that portion of the vane of the 

 feather immediately underneath. 



It is significant that, in the Berlin fossil, the bones of the cubitus 

 lie above the level of the remiges, and that the bases of all these 

 feathers are completely obliterated. This latter fact suggests that 

 they have suffered disintegration owing to their intimate connection 

 with the decomposing muscles and tendons in which they were 

 imbedded. 



Looking at the fossil, one feels tempted to regard a peculiar 

 triangular area between the humerus and cubitus of the left wing as 

 an impression of the patagium. 



Dr. Hurst has described " a series of feathers, which may perhaps 

 be classed as rectrices, along the sides of the hinder part of the trunk, 

 . . . these lateral rows of feathers constitute with the tail-feathers 

 a continuous aeroplane, extending forwards as far as the posterior edge 

 of the extended wings." Though I looked most carefully, I entirely 

 failed to see anything approaching such an aeroplane. The tail- 

 feathers I made out to decrease in length from behind forwards, and, 

 at about the fourteenth caudal vertebra, to pass almost insensibly into 

 larger, somewhat backwardly curved, and decidedly weaker feathers 

 which cease in the region corresponding with the level of the preaxial 

 border of the femur. Of the tibial quills which have been described, 

 I can only say that I saw a mass of feathers which by no stretch of the 

 imagination could I liken to the clearly-defined rectrices and remiges; 

 rather do they resemble a precisely similar series to be found on the 

 tibio-tarsus of some modern birds, e.g., Accipitres. 



That the humerus lacked a pectoral crest, and that the bones 

 were not pneumatic, are statements that have more than once been 

 made. A reference to the numerous photographs, or better still, to the 

 fossils, shows at once that the pectoral crest was in reality fairly 

 developed. That the long bones were pneumatic cannot be definitely 

 disproved, inasmuch as in both the London and the Berlin fossil, 

 wherever these bones are broken they are seen to be filled with crystal 

 (calcium carbonate), the bone having the appearance of a thin in- 

 vesting sheath just as in fossil bones that are admittedly pneumatic. 

 The existence of the pneumatic foramen has been denied, on the 

 ground that there is no trace of it in either fossil. That there 

 should be any such trace was hardly to be expected, since the crista 

 inferior which lodges this foramen is yet imbedded in the stone. 



Whence comes the evidence that the pelvis of Archceoptevyx was 

 conspicuously unlike that of modern birds in the matter of width ? 

 In these latter, the pelvis is supposed to have widened considerably 

 to allow for the backward displacement of the viscera. Since the 

 width of the pelvis is largely determined by that of the sacrum, the 

 little evidence we have, if of any value at all, shows rather that the 

 width of the pelvis of Arclwopteryx was greater, not less, than in living 



