618 



AVES BIRDS. 



Fig. 283. 



second, fills it up, and constitutes the firmest part of the organ. 

 Most of the grooves and folds visible during non-erection become 

 much less apparent when the penis is protruded ; and their direc- 

 tion being oblique, they prevent it from stretching out in a straight 

 line, but oblige it to assume a cork-screw appearance. A deep 

 groove runs along the whole length of this singular organ ; and it 

 is into the commencement of this groove that the vasa deferentia 

 pour the seminal secretion. 



(689.) The females of species whose males possess a large 

 penis, are provided with a rudimentary clitoris of similar con- 

 struction. 



(690.) The female ge- 

 nerative system in the fea- 

 thered tribes offers a remark- 

 able exception to what we 

 have as yet seen in the ver- 

 tebrate Ovipara. Instead of 

 being symmetrically develop- 

 ed upon the two sides of the 

 body, the right oviduct, and 

 most frequently the corre- 

 sponding ovarium, remain 

 permanently atrophied ; and, 

 although they do exist in a 

 rudimentary condition, they 

 never arrive at such dimen- 

 sions as to allow them to 

 assist in the reproductive 

 process. 



(691.) The fertile ova- 

 rium presents in all essen- 

 tial circumstances the same 

 organization as those of the 

 Reptilia ; and is in the same 

 Avay attached by folds of 

 peritonaeum in the vicinity of the spine (fig. 283, /). The 

 contained ova are found in all stages of maturity ; and, being con- 

 nected together by narrow pedicles, the viscus assumes a distinctly 

 racemose appearance. 



The oviduct (d, e) commences by a wide funnel-shaped aperture, 

 and soon assumes the appearance of a convoluted intestine. Its 



