. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. m TSE DESCENT OF MAN. gexes. In the Tetrao cuptdo (fig 39) tlie maie has two bare^ orange-colored sacks, one on each side of the neck ; and these are largely inflated when the male, during the breeding-season, makes his curious hollow sound, audible at a great distance. Audubon proved that the sound was. o '2 *E o E- ^ intimat;ely connected with this apparatus (which reminds us of the air-s&cks on each side

• Contributor: Paul Fearn / Alamy Stock Photo
• Image ID: RCXK11
• File size: 7.2 MB (681.7 KB Compressed download)
• Releases: Model - no | Property - no
• Dimensions: 1347 x 1856 px | 22.8 x 31.4 cm | 9 x 12.4 inches | 150dpi

More information

This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.

This image could have imperfections as it’s either historical or reportage.

. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. m TSE DESCENT OF MAN. gexes. In the Tetrao cuptdo (fig 39) tlie maie has two bare^ orange-colored sacks, one on each side of the neck ; and these are largely inflated when the male, during the breeding-season, makes his curious hollow sound, audible at a great distance. Audubon proved that the sound was. o '2 *E o E- ^ intimat;ely connected with this apparatus (which reminds us of the air-s&cks on each side of the mouth of cer- ain male frogs), for he found that the sound was much dimiuisned when one of the sacks of a tame bird was pricked, sni^ when both were pricked it. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Darwin, Charles, 1809-1882. New York : A. L. Burt