GENERATION AND DEVELOPMENT. 239 



are intermingled fibres of nnstriped muscle. The latter become enor- 

 mously developed during pregnancy. (3.) The mucous membrane of the 

 uterus will be described more in detail presently (p. 21%, Vol. II.). It is 

 lined by columnar ciliated epithelium, which extends also into the interior 

 of the tubular glands, of which the mucous membrane is largely made 

 up. (Allen Thomson, Nylander, Friedliinder, John Williams.) 



The cavity of the uterus corresponds in form to that of the organ 

 itself: it is very small in the unimpregnated state; the sides of its mucous 

 surface being almost in contact, and probably only separated from each 

 other by mucus. Into its upper part, a.t each side, opens the canal of 

 the corresponding Fallopian tube: below, it communicates with the 

 vagina by a fissure-like opening in its neck, the os uteri, the margins 

 of which are distinguished into two lips, an anterior and posterior. In 

 the mucous membrane of the cervix are found several mucous follicles, 

 termed ovula or glandulae Nabothi: they probably form the jelly-like sub- 

 stance by which the os uteri is usually found closed. 



The vagina is a membranous canal, five or six inches long, extending 

 obliquely downward and forward from the neck of the uterus, which it 

 embraces, to the external organs of generation. It is lined with mucous 

 membrane, which in the ordinary contracted state of the canal is thrown 

 into transverse folds. External to the mucous membrane the walls of 

 the vagina are constructed of fibrous tissue, within which, especially 

 around the lower part of the tube, is a layer of erectile tissue. The 

 lower extremity of the vagina is embraced by an orbicular muscle, the 

 constrictor vaginae; its external orifice, in the virgin, is partially closed 

 by a fold or ring of mucous membrane, termed the hymen. The external 

 organs of generation consist of the clitoris, a small elongated body, situ- 

 ated above and in the mdidle line, and constructed, like the male penis, 

 of two erectile corpora cavernosa, but unlike it, without a corpus spongi- 

 osum, and not perforated by the urethra; of two folds of mucous mem- 

 brane, termed Idbia interna, or nymphce; and, in front of these, of two 

 other folds, the labia externa, or pudenda, formed of the external integu- 

 ment, and lined internally by mucous membrane. Between the nymphse 

 and beneath the clitoris is an angular space, termed the vestibule, at the 

 centre of whose base is the orifice of the meatus urinarius. Numerous 

 mucous follicles are scattered beneath the mucous membrane composing 

 these parts of the external organs of generation; and at the side of the 

 lower part of the vagina, are two larger tabulated glands, named v-ulvo- 

 vaginal, or Duverney's glands, which are analogous to Cowper's glands in 

 the male. 



Discharge of the Ovum. In the process of development of indi- 

 vidual Graafian vesicles, it has been already observed, that as each in- 

 creases in size, it gradually approaches the surface of the ovary, and when 

 fully ripe or mature, forms a little projection on the exterior. Coincident 



