818 DEVEL0P3,IEXT OF THE EErEODUCTlYE ORGANS. 



each primordial ovum is closely embraced. A uniform layer of such 

 ova of nearly equal size is especially to be found tovs^ards the surface ; 

 but in the two later months of foetal life some of the ova and follicles 

 advance to a farther stage of development, and increase in size, and 

 this advance is invariably accompanied by a change of position of these 

 ova to a deeper stratum of the ovary. The most advanced of the ova, 

 therefore, are situated deepest in this the earlier stages of the ovarian 

 development. It is different, however, when some "years after Ijirth, 

 and still more towards the age of puberty, a few of the Graafian follicles 

 expand to a great extent, and ultimately when mature reach the 

 diameter of about a quarter of an inch, for then the expanding 

 Graafian follicle gradually approaches the surface of the ovary, or 

 perhaps rather, during the rapid expansion of the follicle, the ovarian 

 stroma gives way by absorption between the follicle and the surface. 



As the Graafian follicle expands with the slightly enlarging ovum, the 

 thickness of the layers of condensed connective tissue or stroma round 

 the ovum increases, and thus there are gradually formed the layers which 

 liave been described as the follicular walls, while blood-vessels penetrate 

 into them so as to form the vascular network of the covering. Within the 

 follicle the granular cells multiply so as to form several layers lining the 

 •whole follicle and closely covering the ovum. As yet there is no space 

 between the ovum and wall of the follicle except that which is occupied 

 by the granular cells, and for a long time the follicle is not larger than 

 to enable it to enclose the ovum ; but in the more advanced stages a 

 proportionally great enlargement of the follicle takes place, in conse- 

 quence of the separation of two layers of the granular cells, so as to 

 form a space in which fluid accumulates, and thus one or more layers 

 •of cells are left lining the expanded follicle and constituting its tunica 

 granulosa, while those covering the ovum, which is now thrown to one 

 side of the follicle, form the investment known as the discus proligerus, 

 -which appears as a reflected portion of the tunica granulosa (see 

 figs. 335 and 336, p'3. 473 and 475). 



As connected with the difference in the seat and mode of development of the 

 ■essential parts of the male and female productive organs, the important question 

 presents itself of the possibility or reality of the simultaneous coexistence in any 

 cases of malformation of ovaries and testes on one or both sides of the body in 

 the same individual. From what has been stated above, the possibility of such 

 coexistence may perhaps be theoretically admitted. On this subject the reader 

 may consult an interesting account by Dr. C. L. Heppner of St. Petersburg 

 (Reichert's and Dubois Reymond's Ax-chiv for 1870, p. 679), of a hermaphroditic 

 child which lived two months after biiiih, in which, along with a considerable 

 amount of the better kno-mi conditions of approximation or mingling of the 

 sexual charapters, it appeared that two organs coexisted, in one of which, agreeing 

 in all respects with the ovary, primordial ova in Graafian folUcles were observed, 

 and in another of a distinctly rounded iorm and compact structm'e, and so far 

 corresponding to the testicle and unlike any of the other known vestigial organs, 

 branched and coiled tubes, filled with cells in a manner exactly the same as 

 those of the seminal canals, were ascertained by microscopic observation to exist. 

 The jiarovarium (epididymis or coni vasculosi) also existed. 



The genital passages. — The existence of two sets of tubes between 

 the iuteinal productive organs and the external parts has already been 

 adverted to as a feature common to both sexes. The female organs con- 

 trast Avith the male in the large development of one of these tubes, viz.. 



