IfOTEMBER 1, 1912] 



SCIENCE 



599 



iramming-birds and swifts, and some of the 

 best flyers among parrots have an imperfect 

 •lavicle. 



Chapter three deals with motive power, 

 Average, propulsion, wing stroke and the man- 

 »er in which the wings attack the air, a man- 

 ner well described on page 45. 



Here, too, a query. Mr. Headley thinks 

 that the kestrel can not hover unless the wind 

 is blowing against him. We believe that the 

 kingfisher can do this, and the humming-bird 

 and hawk moth will hover above a flower and 

 •ircle around it with no apparent difficulty. 

 Mr. Headley points out that quality of muscle 

 is quite as important as quantity, and notes 

 that while ordinarily the elevator muscles are 

 inferior to the depressor, in the guillemot, a 

 swimming bird, they are on a parity. Un- 

 doubtedly his explanation is correct; the bird 

 that uses its wings to fly beneath the water 

 »eeds powerful muscles to raise them. This 

 i« in line with the deeply keeled sternum and 

 abundant muscles of the penguin and great 

 auk, birds incapable of aerial flight, that wing 

 their way swiftly beneath the water. 



Further chapters deal with the relation be- 

 tween the form of wings and mode of flight, 

 speed and endurance and the influence of the 

 wind. Here we find repeated the theory that 

 soaring (circling upward) is made possible by 

 upward currents of wind, a theory that we 

 think few will find satisfactory. A bird may 

 •ircle about in such a current, but it would 

 »ot have strength enough to raise him and we 

 ieel that the most that can be said is that in 

 gome way, as yet beyond our power of imita- 

 tion, birds, so to speak, screw themselves 

 through the air to vast heights, over the level 

 pampas as well as over the gusty mountain 

 tops. 



But one can not indulge in much discussion 

 ia little more than 150 pages and the average 

 leader will prefer to have the facts rather than 

 theories: and Mr. Headley has done well to 

 jjive us so many facts and so much well-told 

 iaiformation in so small a compass. 



A feature of the book are the illustrations 

 •f birds, mainly pigeons, and for the most 

 part from Mr. Headley's photographs, in 



various phases of flight. These give an idea 

 of the varied poses of the wings and tail, and 

 their relation to the balance of the bird, or 

 direction of its flight, that can not be gained 

 from words. 



F. A. L. 



SPECIAL ABTICLES 

 THE EVENING PRIMROSES OF DIXIE LANDING, ALA- 

 BAMA 



Bartram's locality for (Enothera grandi- 

 fiora at Dixie Landing on the Alabama Eiver 

 some distance above Fort Minams (1778) was 

 rediscovered by Professor S. M. Tracy in 

 1904 and visited a second time by him in 

 1907. Seeds procured by Tracy have been 

 widely distributed and have given rise to races 

 of (Enothera grandiflora which are being 

 studied by several investigators. 



(Enothera grandiflora is one of the nearest 

 allies of (E. Lamarchiana and seems to agree 

 with that species in at least some points per- 

 taining to mutability and behavior on hybrid- 

 izing. Its study may at some time lead to an 

 explanation of those phenomena which until a 

 short time ago seemed peculiar to (E. Lamarch- 

 iana. Consequently it seemed to us to be of 

 primary importance to study CE. grandiflora 

 in its original habitat, and we visited Dixie 

 Landing under the kind guidance of Pro- 

 fessor Tracy, on September 26 and 27. 



It had been known from cultures grown 

 by Professor B. M. Davis from Professor 

 Tracy's wild seed that (E. grandiflora did not 

 occur at Dixie Landing as a single pure strain. 

 It was no surprise, therefore, to find growing 

 in the old cotton fields several forms of (E. 

 grandiflora, together with several forms of its 

 companion species (E. Tracyi, which has re- 

 cently been described by one of us. The 

 plants were partly in flower and partly in the 

 rosette condition. Neither CE. grandiflora nor 

 (E. Tracyi has heretofore been known as other 

 than annual, and the abundance of rosettes 

 which would obviously not flower this season 

 was therefore a point of great interest. Seeds 

 were obtained from all strains which had ripe 

 capsules, and in addition a large collection of 



