408 JOHN LEWIS BREMER 



In several embryos and in a fetus of three months and another 

 of seven months I have found tubules lymg in the rete region and 

 yet unconnected with the rete cords (fig. 4, 4 and i 5). In the 

 older fetus such tubules are of smaller diameter than the ductus 

 epididymis, but have a similar epithelium. If separated from 

 their neighbors, these tubules would form the lower ductulus 

 aberrans. The upper paradidymis of Toldt (organ ofGiraldes) 

 is probably correctly described by him as mesonephric tubules 

 lying below the rete region but maintaining their connections 

 with the duct. 



While not dealing in this paper with the histological differen- 

 tiation of the epithelium lining these tracts, I may mention that 

 this differentiation seems to depend not on the portion of the 

 mesonephric tubules or duct which gives rise to any tubule in the 

 adult, but on the connections which are permanently established. 

 At three months the epithelium of the tubules and duct is similar, 

 all trace of former differentiation having disappeared; at about 

 seven months a new differentiation takes place, but this time all 

 the tubules connected with the rete show a similar epithelium, 

 all tubules connected with the duct have duct epithelium. Thus 

 tubules of like origin may at seven months and later be lined by 

 different kinds of epithelium. The similarity of the epithelium 

 in the duct and the blind tubules emptying into it seems to me 

 to point distinctly toward a secretory function of this coiled tube. 



As will be seen from the diagrams, (which have been compiled 

 after carefully following each tubule in serial sections of the or- 

 gans, and which have been offered instead of models or actual 

 reconstructions, as showing more clearly the courses and connec- 

 tions of the different tubules), there are several cases of branching 

 in each epididymis, as found by MacCallum and Grafe in the 

 Wolffian body. In only one fetus was an anastomosis found (fig. 

 4, 1 and 2), and the formation of a more considerable network was 

 nowhere seen. It is probable that tubule 5, in the same diagram, 

 originally anastomosed with tubule 4 or some other, since in this 

 way the position of the persistent glomerulus may be explained, 

 by imagining two tubules running to the same glomerulus, only 



