654 OLD MAN—OLIGOMYODjE 



Pigeons as Didunculus (Dodlet), Goura and Treron; in other 

 Cockatoos, in several PARROTS (Chrysotis and Pionus), in Podargns 

 (Nightjar), Otis, Argusanus and the Ratitai it is absent. This irregu- 

 larity shews that it has not much value as a taxonomic character ; 

 but attention to other peculiarities in its form or structure has been 

 drawn by Nitzsch and Garrod, and especially to the presence or 

 absence of a circlet of feathers surrounding the nipple-like orifice, 

 and when that occurs the skin covering the gland is naked, while 

 when the circlet is wanting the whole is covered with down inter- 

 spersed with stiff feathers. Among the birds to which the last 

 condition applies are the Bucconidse, Caprimulgi (excl. Podargus)^ 

 Cariama, Coradidse, Cuculidx, Cypseli, Galbulidse, Leptosomus, Mero- 

 pidm, Momotidse, Steatornis and Trogonidse, while by far the greater 

 number of birds possess the tuft. 



Analysis of the secretion of the Oil-gland shews that its com- 

 position closely resembles that of the sebaceous product of Mammals ; 

 but that it differs from milk through the absence of sugar. Its use 

 is px'obably the anointing of the plumage, and the presence of 

 Powder-downs in Cacatua, Chrysotis and Podargus may possibly 

 indicate some correlation between these organs and the oil-gland.^ 



OLD MAN, the name in Jamaica for Hyetornis pluvialis, one of 

 the CucKOWS which is also called Rain-bird, as are others of the 

 Family. 



OLD SQUAW and OLD WIFE are two of the many names of 

 the Long-tailed Duck, the former necessarily of transatlantic oi'igin. 



OLEGPiANON, the proximal end of the Ulna, projecting back- 

 ward from and beyond its articulation Avith the Humerus, being 

 practically equivalent to the point of the elbow. It serves as a 

 lever during the extension of the wings, the tendons of the triceps 

 muscle beino; inserted on the Olecranon. 



OLIGOMYOD^, Prof. Huxley's name {Proc. Zool. Soc. 1867, 

 p. 471) for the group of Passerine Birds having but few song- 

 muscles (Syrinx) which Johannes Miiller had previously called 



PiCARII. 



1 It seems that it would be improper here to overlook a controversy on this 

 still unsettled question which, though now wholly forgotten, was carried on, to 

 the amusement of our predecessors, in the later volumes of Loudon's Magazine 

 of Natural History, and in the early years of The Zoologist. Waterton, with 

 the mistaken zeal he so frequently exhibited, maintained that the gland had no 

 lubricating function, chiefly because he had observed that the so-called "rump- 

 less " breed of Fowls, in which the gland is wanting, kept their feathers as glossy 

 as other Fowls which possessed it. He was easily victorious so long as he had to 

 deal only with the late Mr. F. 0. Morris, but Avhen he met with an adversary 

 like the late ilr. C. A. Bury, who knew something about birds, was a good 

 ol)server and could write rationally, Waterton's mistaken position seems to have 

 become plain to him, and he retired from the contest. — A. N. 



