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ON A CURIOUS HORN-LIKE EXCRESCENCE 

 ON A LAPWING. 



BY 



C. B. TICEHURST, m.a., b.c, m.r.c.s., m.b.o.tt. 



On Februar}^ 9th, 1910, I received for examination 

 through the Editor of British Birds from ^Messrs. W. 

 J. WiUiams, taxidermists, of Dubhn, a skin of a female 

 Lapwing {Vanellus vulgaris) which had been shot a few 

 days before in co. Waterford, Ireland. Springing from 

 the root of the tail was a large horn-like " growth," 

 which hung do\Aai over the basal half of the tail. This 

 " horn " measured in total length 7 inches ; its base, 

 which was the A^-idest part, measured 2 inches in circum- 

 ference and I inch in diameter ; it gradually tapered to 

 a blunt point, and formed one spiral and a hah, curhng 

 from right to left ; its surface was smooth, very hard, 

 and in places irregularly striated. On examining its 

 origin more closely I found that it sprung from a part of 

 the oil-gland, and, indeed, was continuous ^\dth the 

 remains of that structure, which still retained some of 

 its secretion. The oil-gland is a bilobed structure 

 situated beneath the skin on the last free vertebra 

 and the bases of the rectrices ; the two lobes, which are 

 separated anteriorly, are united posteriori}^ and open 

 in a common cavitj' or an elongated process ; this process 

 in many birds {Gallinacece and aquatic birds, etc.) is 

 encircled by a small tuft of feathers. The gland consists 

 of closely -packed, parallel, fihform tubules, which secrete 

 the sebaceous unguent with which the plumage is preened ; 

 it is largest in aquatic birds, small in passerine birds, 

 whilst in some (Otis, Casuarius, StrutJiio, Rhea, some 

 pigeons and parrots) it is said to be absent. The secretion 

 is usuall}^ only shghtly odorous, except in Anas moschata 

 and Upiipa ejjops, in which it has a pronounced smell. 

 The gland is encapsuled in a covering which contains 



