PHYLUM CHORDATA 



379 



which is widely distributed in the Palsearctic and Oriental regions. 

 The following description refers especially to the common Dovecot 

 Pigeon. 



External Characters. In the entire Bird (Fig. 1022) the 

 plump trunk appears to be continued insensibly into the small, 

 mobile head, with its rounded brain-case and prominent beak, 

 formed of upper and lower jaws covered by horny sheaths. The 



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FIG. 1022. Colunxba livia. The entire animal from the left side with most of the feathers 

 removed, ad.dg.rm.r. ad-digital remex ; al. sp. ala spuria ; an. anus; au. ap. auditory 

 aperture ; cb. rmg, cubital remiges ; cr. cere ; dg. 1, 2, 3, digits of manus ; dg. 1', 2', 3', U ', 

 digits of pes ; hu. pt. humeral pteryla ; lg. ligament of remiges ; md. dg. rmg. mid-digital 

 rcrniges ; na. nostril ; net. m. nictitating membrane ; o. gl. oil-gland ; pr. dg. rmg. pre-digital 

 remiges ; pr. ptfim. pre-patagium ; pt. ptgm. post-patagium ; ret. mesial rectrix of right side ; 

 ret', sacs of left rectrices ; sp. pt. spinal pteryla ; ts. mlts. tarso-metatarsus ; v. apt. ventral 

 apterium. 



head, neck, and trunk are invested in a close covering of feathers, 

 all directed backwards and overlapping one another. Posteriorly 

 the trunk gives origin to a number of outstanding feathers which 

 constitute what is ordinarily called the tail. From the anterior 

 region of the trunk spring the wings, also covered with feathers, 

 and, in the position of rest, folded against the sides of the body. 

 The legs spring from the hinder end of the trunk, but, owing to 



