456 



MANUAL OF ZOOLOGY 



SECT. 



imperfectly-marked digits, the second (dg. 2) much larger 

 than the first (dg. i) and third (dg. j), can be distinguished. 



,a.u.ajy 



rcl 



^ 



rcl' 



u 



fc 



V i \ \\Y\j 



\\\y 



FIG. 257. Columba livia. The entire animal from the left side with most of the 

 feathers removed, ad. dg. mix. ad-digital remex ; al. sp. ala spuria ; an. anus ; 

 an. ap. auditory aperture ; cb. ring', cubital remiges ; cr. cere ; dg. /, 2,.?, digits 

 of manus ; dg. /', 2 r ,j', 4', digits of pes ; hn.pt. humeral pteryla ; Ig. ligament 

 of remiges; t>td. dg. nag. mid-digital remiges; na. nostril ; net. m. nictitating 

 membrane; o.gl. oil-gland; pr. dg. nng. pre-digital remiges; pr.ptgtn.^r^- 

 patagium ; pt. ptgin. post-patagium ; ret. mesial rectrix of right side ; ret', sacs 

 of left rectrices ; sp, pt. spinal pteryla ; ts. intts. tarso-metatarsus ; 7'. apt, 

 ventral apterium. 



In the position of rest the three divisions of the wing are 

 bent upon one another in the form of a Z : during flight the 



