250 



ANATOMY OF VEETEBRATES. 



128 



The o\'iduct in the quiescent state is generally straight, but at 

 the period of sexual excitement it is augmented in length as well 

 as capacity, and describes three principal convolutions before 

 reaching the cloaca, fig. 128, n. The lining membrane presents a 

 different character in different parts of the oviduct ; at the infundi- 

 bulum, ib. e, the surface is longitudinally rugous : lower down the 

 lining membrane begins to be disposed in oblique ridges, ib. g, 

 beset with follicular glands: at the more contracted part, or 



' isthmus,' they become longitudinal 

 and subside : in the terminal dilata- 

 tion, ib. k, the lining membrane is 

 beset with large flattened villi, con- 

 tainino- the follicles concerned in the 

 secretion of the shell. The whole 

 oviduct is lined by vibratile epithe- 

 lium. The shell-forming part has 

 been termed the ' uterus,' but the 

 ovum is never developed in it. The 

 rest of the canal, /, which, by the same 

 loose analogy, is termed ' vagina,' 

 opens into the urogenital segment 

 of the cloaca, anterior to the orifice 

 of the left ureter, and its termination, 

 figs. 86, 109, y*, is provided with a 

 sphincter. 



The mesometry, fig. 128, 7?z, differs 

 most from the mesentery when the 

 female organs are in full sexual 

 action. It presents at that period 

 a muscular structure, but the fibres 

 are not striated. It is divided into two parts, one superior, the 

 other inferior. The inferior mesometry has its point of attach- 

 ment at the lower part of the uterine portion of the oviduct, and 

 forms a somewhat dense and cruciform plexus of muscular fibres 

 radiating from that part. The transverse fasciculi are spread out 

 on either side and around the uterus. The lower fasciculus sur- 

 rounds the vagina more laxly, and contributes to the expulsion of 

 the ovum. The upper fasciculus spreads out like a fan upon the 

 oviduct from its insertion into the uterine portion to the com- 

 mencement of the infundibulum. 



The superior mesometry commences by a firm elastic ligament, 

 which is attached to the root of the penultimate rib of the left- 

 side, whence the muscular fibres are continued to the upper part of 



Female organs, Fowl, at breeding season. 



XXXIV. 



