^°^i9io^"] Recent Literature. 235 



almost universally been regarded as a case, unique among birds, of inten- 

 tional self-mutilation, presumably for the purpose of ornamentation. 

 Furthermore, as the rectrices exhibit a narrowing of the vane at the point 

 where later denuded, this has been used by those who believe in the inheri- 

 tability of acquired characters as evidence in support of their views. 



As far back as 1885 Dr. Stejneger figured the tail of a specimen that had 

 the middle feathers partly bare although the tail was only half grown. 

 In his remarks he came very near the true solution of the problem, but 

 his surmises were not quite correct in detail. 



Mr. Beebe's conclusions are based on the stvidy of a live specimen of 

 Momotus lessoni and on the examination of skins of various species. 



In the captive bird, on one occasion, the growing rectrices were found 

 to be already denuded while yet enclosed in the sheath; in this case, there- 

 fore, any trimming by the bird, intentional or otherwise, was wholly pre- 

 cluded. While in this particular instance, the denudation was premature, 

 due probably to the birds' low vitality, yet this condition is approached by 

 another species, Eumomota superciliaris, in which the shaft is stripped for 

 a greater distance than in its allies. Here the dropping of the very short 

 barbs occurs almost as soon as the growing feather is free from the sheath 

 and long before it has reached its full length. 



Upon close examination of the tail feathers of Momotus mexicanus and 

 other species it was found that in the freshly grown feather the portion 

 later denuded differs from the normal part of the vane in ha^'ing the basal 

 part of the barbs almost free from barbules and the barbs themselves 

 slightly weaker than usual. This naturally renders the barbs liable to 

 break away from the shaft at the point of connection. 



Mr. Beebe concludes that the trimming of the feathers is not intentional 

 on the bird's part, but is merely incidental to the ordinary preening of the 

 plumage, a,nd that no inheritance of acquired characters is necessary to 

 explain the constriction of the vane, both this feature and the basal de- 

 generation of the vane being congenital and due to some wholly unknown 

 cause. — W. De W. M. 



'Cassinia.' — 'Cassinia, A Bird Annual,' has again promptly made its 

 appearance, this being the tenth issue of the 'Proceedings' of the Delaware 

 Valley Ornithological Club of Philadelphia under this title, and forming 

 No. XIII of the Proceedings of this active organization, which on January 

 6 of the present year celebrated its twentieth anniversary. As usual, it 

 sticks to its text, the "Ornithology of Pennsylvania, New Jersey and Dela- 

 ware," but, under the continuous editorship of Mr. Stone, contains, also 

 as usual, matter of wide interest. The editor contributes another of his 

 happy sketches of early Philadelphia ornithologists, this time dealing 

 with the late Dr. Thomas B. Wilson, so well known as the liberal patron 

 of the Academy of Natural Sciences of Philadelphia, to whose gifts the 

 Academy owes its almost unrivalled natural history library and the 

 Rivoli, Gould, and other notable collections of foreign birds, purchased 



