308 OSWALD S. LOWSLEY 



The tubules of the lateral lobes arise from the sides of the ure- 

 thra and from the bottom and in some cases a little to the inside 

 of the depressions at the sides of the urethra, which are commonly 

 called prostatic furrows. These structures are in nearly every 

 case larger than the ones making up the middle lobe. They are 

 thirty-nine in number, twenty-six of which are arranged definitely 

 in pairs and three of which are unpaired send branches forward. 



In this series no glandular tissue is noted in the region dorsal 

 to the ejaculatory ducts. At the lower or caudal end of the pros- 

 tate the tubules become centrally located near the midline and 

 here we have structures which later grow back dorsally to the 

 ejaculatory ducts and become the posterior lobe of the prostate. 

 Beginning evaginations and tubules occur throughout the pros- 

 tatic urethra on its roof or ventral wall. The general direction of 

 the growth in this region as well as in the others is bladderwards 

 with the exception of the outermost of the lateral lobes and the 

 posterior lobe which send a few branches caudalward. The 

 .tubules of the ventral lobe are twelve in number, eight of which 

 are paired, the other four being directly in the middle line. One 

 of the latter tubules is quite long and presents a very definite 

 lumen as all of the larger ones do; those smaller in size are nearly 

 all solid epithelial outgrowths. 



There are no glandular outgrowths from the urethra below the 

 apex of the prostate and there are no signs of glandular growth in 

 the subcervical region where Albarran's tubules are found in 

 later stages. 



The vasa deferentia appear under the bladder at the entrance 

 of the ureters as two small tubes surrounded by a thick layer of 

 developing muscle and connective tissue. As they descend they 

 approach each other and behind the middle of the trigonum vesi- 

 cae they are enveloped in the same tissue, being bound very firmly 

 together, and between them is noticed a very small lumen sur- 

 rounded by rather delicate but distinct connective tissue layers, 

 which is taken to be the unobliterated upper portion of the fused 

 Miillerian ducts. The vasa deferentia and their enveloping 

 tissue increase enormously in size as they descend, so that under 

 the internal sphincter this structure is larger than the beginning 



