. Key to North American birds [microform] : containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland. Birds; Ornithology; Oiseaux; Ornithologie. 216 GENERAL ORNITHOLOGY. product of the malo function to tlio cloaca, just as tho oviduct convoys the prodtict of tho female fuTiction to tho same aewcragc. Thus the testicle of the male and tho ovary of tho female are homologous, in fact primitively identical organs, ui>on which sexual difforoneo is impressed hy the greater eo
. Key to North American birds [microform] : containing a concise account of every species of living and fossil bird at present known from the continent north of the Mexican and United States boundary, inclusive of Greenland. Birds; Ornithology; Oiseaux; Ornithologie. 216 GENERAL ORNITHOLOGY. product of the malo function to tlio cloaca, just as tho oviduct convoys the prodtict of tho female fuTiction to tho same aewcragc. Thus the testicle of the male and tho ovary of tho female are homologous, in fact primitively identical organs, ui>on which sexual difforoneo is impressed hy the greater eomjilexity fif structure acquired if tho sex is to bo malo; a female being, anatomi- (â¢ally and physiologically, simply an imperfect male, arrested at one stage of her jjhysical progress to male perfection of structure; and tho whole nature of the female boars out the sunio relati(m of inferiority. But the oviduct of the female, and the spenn-duct of the male, thmigli physicdogically identical, having the same function of conveying the products of geueratiou from tho genital gland to the light of day, are not anatomiailly tho same; for in tho case of ilie female, whose wolffian duct has disappeared, the miillerian is tho oviduct; in tho ease of tlie male, in which no miillerian duet appears, the wolffian is tho spi-rm-diu-t. Tho two are analo- gous, not homologous (a good illustrati(m â see p. 68). IJut it must ho further observed tl at whih' tho sperm-duct conveys (mly tho masculine es.'^enco from centre to periphery, the ovliiiict conveys the feminine material from centre to periphery, and (duo the male in the opixisiie direction ; for, upon coitus, which is direct in all birds, the spermato/.oa, deposited in the cloaca of tho female, find their way up through her oviduct to the ovary, there to accomplish iuijireg- nati6v, uon, an egg) ; though the term is vulgarly used to signify merely a of tho chalky substance in which the egg of a bird is finally
Size: 1188px × 2104px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectbirds, bookyear1884
