92 BENJAMIN H. WILLIER 



end of the gonad; this vascular cord is loosely bound with a vas 

 deferens to form a spermatic cord. 



The tunica albuginea and tunica vasculosa. A study of the 

 connective tissue capsule of these three gonads indicates that it 

 also may be rather completely transformed in the male direction. 

 The average thickness of the capsule is about 0.8 mm. which is 

 several times thicker than in the capsules from gonads less 

 transformed, and which approaches very closely the normal 

 thickness of 1 mm. in the testis of an adult. As in the other 

 groups, the inner layer of the connective-tissue capsule is modi- 

 fied by the addition of blood-vessels, constituting therefore a 

 vascular zone. This zone varies in the different gonads of this 

 group. In case 44 it is poorly formed, yet at places a distinct 

 layer is present containing blood-vessels which pass in a cen- 

 tripetal direction to the sexual cords. In addition, blood-vessels 

 also enter the hilus to be distributed in a centrifugal manner to 

 the sexual cords. In case H-46 (fig. 10, tv) is seen a very definite 

 vascular zone, from which blood-vessels are distributed centri- 

 petally to the sex-cord region. The existence of the tunica 

 vasculosa in case H-37 as a distinct layer is lost by its close 

 mergence with the outer layer, the two constituting the tunica 

 albuginea, the inner portion of which contains the blood-vessels. 

 In contrast to the coarse condition of the fibers in less trans- 

 formed gonads, the fibers are fine in H-37. The fineness of the 

 fibers and the mergence of the two layers into one tunica albu- 

 ginea, resemble in close detail the structure of the normal testis 

 (table 3). 



Upon the tunica albuginea is a single layer of flattened epi- 

 thelial cells, which constitutes the visceral layer of the tunica 

 vaginalis. 



The sex-cord region. The sex-cord regions of these three 

 free-martin gonads have reached the highest degree of differen- 

 tiation, organization, and largest size of any of the post-natal 

 gonads. The primitive relationships of the sex-cord region to 

 the core of rete tubules is shown by the eccentric position of the 

 latter. The sex-cord region completely surrounds the rete cord, 

 and this is a distinct advance in the male direction where the 



