328 



HISTOLOGY 



lying mesenchyma appear to form a continuous protoplasmic network, 

 and "the stroma cells are practically identical with the peritoneal cells 

 from which they are originating." But Allen concludes that " the tubules 

 of the testis are formed as solid invaginations of the peritoneum, which 

 later become separated from it, and grow by the activity of their compo- 

 nent cells." There is, then, a difference of opinion as to whether the 

 tubules of the testis are formed directly from the stroma within the 

 genital ridge (Felix), or as invaginations from the peritoneal epithelium 



FIG. 326. FROM A RECONSTRUCTION OF A 13.6- 



MM. HUMAN EMBRYO. (F. W. Thyng.) 

 bl., Bladder; f., fimbriae; g. g., genital ridge; g. p. 



FIG. 327. DIAGRAM OF THE DEVELOPMENT"[OF 

 THE TESTIS, BASED UPON FIGURES BY MAC- 

 CALLUM AND B. M. ALLEN. 



Diaaaer; i., nmonse; g. g., genual riage; g. p.t " 



genital papilla; "M. d., Mullerian duct; p., c., Glomerular capsule; i. c., inner or sex cords; 



renal pelvis; r., rectum; ur., ureter; u s. t M. d., Mullerian duct: o. c. f outer or rete 



urogenital sinus; W. d., Wolffian duct. cords; W. d., W. t., Woiffian duct and tubule. 



(Allen). A figure of an ii-mm. human embryo published by Felix ap- 

 pears to accord with Allen's interpretation, and such a condition is shown 

 diagrammatically in Fig. 327. 



As the cords become detached from the peritoneum, they form arching 

 anastomoses, convex toward the periphery of the ridge; and with further 

 growth they become greatly convoluted. They acquire lumens, and 

 become the tubuli contorti, in the walls of which spermatogenesis takes 

 place. The shapes presented by these tubules in the embryo have been 

 carefully modelled by Bremer (Amer. Journ. Anat., 1911, vol. n, pp. 

 393-416). 



Toward the interior of the genital ridge the cords become more slender 

 and converge toward the Wolffian body. There they are imbedded in a 

 considerable mass of tissue, which in the adult becomes the mediastinum 

 testis. The inner ends of the contorted tubules, toward the mediastinum, 

 remain straight, forming the tubuli recti; and these, further inward, become 

 thin- walled and anastomose freely, thus constituting the rete testis (Fig. 

 328). 



