216 



GENERAL ORNITHOLOGY. 



product of the male function to the cloaca, just as the oviduct conveys the product of the female 

 function to the same sewerage. Thus the testicle of the male and the ovary of the female are 

 homologous, in fact primitively identical organs, upon whicli sexual dift'erence is impressed hy 

 the greater complexity of structure acquired if the sex is to he niale ; a female being, anatomi- 

 cally and physiologically, simply an imperfect male, arrested at one stage of her physical 

 progress to male perfection of structure; and the whole nature of the female bears out the same 

 relation of inferiority. But the oviduct of the female, and tlie sperm-duct of the male, though 

 physiologically identical, having the same function of convoying the products of generation 

 from the genital ghmd to the light of day, are not anatomically the same; for in the case of the 

 female, whose woltiian duct has disappeared, the niiiUcriau is the ovnhict; in the case of the 

 male, in which no miillerian duct appears, the wolffian is tlie sperm-duct. Tlie two are analo- 

 gous, not homologous (a good illustration — see ]>. 08). Hut it must be further observed that 

 while the spenn-dnct conveys only the nuisculine ess<'nce from centre to periphery, the oviduct 

 conveys the feminine material from centi'c to perijihery, ami also the male essence in the opposite 

 direction ; for, upon coitus, which is direct iu all birds, the speruiatozoa, deposited in the cloaca 

 of tlie female, tind their way up through her oviduct to the ovary, there to accomplish imjireg- 

 nation of the ovarian ova, the fecund product then passing down by the same avenue. All that 

 relates to the mysteries of generation, — both the structure and function of the reproductive 

 organs, and the maturation of the pr(jduct of concepticju, is ])roperly Oiilogy (Gr. oidi/, oon, an 

 egg) ; tliough the tiTm is vulgarly used to signify merely a description of the chalky suhstanc© 

 in whicli the egg of a bird is finally invested. The anatomy of the egg is Emhryology. An 

 egg, or oinim, is siniply the product of conception up to the time that product acquires an inde- 

 pendent existence; .while still connected with the female tissue of the o\ uj aid bcfou oi after 

 it amalgamates with the male element, it is an oviirimi ovum; 

 more or less incompletely matured, it is an embryo or futus, — 



the former term being commonly applied 



to the unhat<died y<iung of liirds. The 



only dift'erence between the "egg"<if a 



"viviparous" mammal and that of an 



"(jviparous" bird, is in the albuminous 



and cretaceous envelopes of the latter, 



and its sjieedy expulsion from the body 



of the feuuile to be hatched outside, with- 

 out anatomical connection with the moth- 

 ( jl^m pllfJ5^ er after the hard shell isformed ; wliereas, 

 X^l.ilv V<-VihE^T in most maninials, the ovum is retained 



in a dilated part cjf the miillerian duct 



(uterus <a- W(unb) untilit " hatches" ; but 



mammal and bird alike ''lay eggs," the 



essential genninative part of which is 



identical 



and a proper idea of the relations of the 



mature sexual organs to the wcdffian become ovary; rf, adrenals; c.urc- 

 1 ,. . ' , 1 . v ters; /, wolffian ducts, to disap- 



bodies IS necessary to any UBderstanamg pear; ,7, mulleriandu.t., to become 

 of th(5 parts and processes concerned in oviducts. 



reproductirm.i We liavc here to consider the permanent as distinguished from the transitory 



kidneys, and may then recur to the suhject of generation. 



Fici 10.1 — Uro-getiil;d 

 organs of male embryo bird; 

 from Owen, after Miiller. 

 a, kidnej's: h, ureters; c, 

 woltfian bodies; d, tlieir 

 ducts, to be sperm -ducts; 

 e, genital glands, to become 

 testicles ; /, adrenals. 



Appreciation of these facts, offemalc embryo bird; from Owen 



after Miiller. a, kidneys; b, wolf- 



Ftg. 104. — TJro-genital organs 



bird ; from Owen, 



I, kidneys; b, wolf- 



an bodies ; c, genital gland, to 



' The matter may be furllier illustrated by tlie two figures borrowed from Owen (after Miiller). In both figs., 

 the large dark masses, a, arc the permanent kidneys, whose ducts, h in fig. 103, c in fig. 104, are the ureters, empty- 

 ing into the cloaca. In fig. 103, male, c is the wolffian body, whose duct, f/, persists as the sperm-duct, conveying 



