FEMALE GENERATIVE SYSTEM. 



741 



Fig. 369. 



(2100.) The oviduct (fig. 369, d, e) commences by a wide funnel- 

 shaped aperture, and soon assumes the appearance of a convoluted intes- 

 tine. Its lining membrane varies in texture in different parts : near the 

 infundibular orifice it is thin 

 and smooth ; further down it 

 becomes thicker and corru- 

 gated ; and at last, near the 

 termination of the canal, where 

 the egg is completed by the 

 calcification of its outward 

 covering (g\ it presents a 

 villose texture. The oviduct 

 ultimately opens into the cor- 

 responding side of the urethro- 

 sexual compartment of the 

 cloaca. 



(2101.) We must in the 

 next place proceed to de- 

 scribe, with as much brevity 

 as is consistent with the im- 

 portance of the subject, first, 

 the nidus, or ovisac, in which 

 the rudiment of the future 

 being is produced; secondly, 

 the structure of the germ 

 (ovulum) when it escapes from 

 the ovary ; thirdly, the addi- 

 tions made to the ovulum as it 

 passes through the oviduct; 

 and lastly, the phenomena 

 that take place during the de- 

 velopment of the embryo by incubation. 



(2102.) If the ovarium of a bird be examined whilst in functional 

 activity, such of the pedunculated ovisacs (calyces, fig. 369, /) as have 

 within them ovula ripe for exclusion will be found to consist of two 

 membranes*. Of these, the exterior is very vascular, and is surrounded 

 with a pale zone (stigma), occupying the centre of the calyx. The 

 lining membrane of the ovisac, on the contrary, is thin and pellucid, but 

 studded with minute corpuscles, which are probably glandular, or per- 

 haps little plexuses of vessels. Within this ovisac the basis of the 

 future egg (ovulum) is formed. 



(2103.) The ovulum produced in the ovisac, when mature, is made 

 up of the following parts. The bulk of it consists of an orange-coloured 

 oleaginous material, enclosed in a most delicate and pellucid membrane 



* Vide Purkinje, Symbolic ad ovi Avium historiam ante incubationem. 4to. 

 Lipsise, 1830. 



Generative apparatus of the Hen. 



