324 OSWALD S. LOWSLEY 



always been possible, as some of the tissue is quite old and con- 

 traction of the epithelium has taken place. 



The two lateral lobes are made up of thirty-six tubules which 

 extend posteriorly and up under the internal sphincter as far as 

 do those of the middle lobe. At the sides of the lower part of the 

 sphincter there is a distinct bulging due to the further develop- 

 ment of the lateral lobe tubules, which with the middle lobe form 

 the base of the gland. This posterior and lateral bulging is noted 

 throughout the entire prostatic region, although the larger num- 

 ber of tubules are massed in the base of the gland. There are a 

 number of tubules whose ducts open into the sides of the urethra 

 and which send branches up towards the ventral wall. These 

 structures have many branches but they are much smaller than 

 either the rest of the lateral or middle lobe tubules and their mus- 

 culature is very slight compared to that of the other prostatic 

 tubules. In the apex of the gland the tubules of the lateral lobe 

 have a few branches which run downward or outward. Every- 

 where else the general direction of growth is towards the bladder. 



The glandular tissue making up the posterior lobe is found at 

 the point where the ejaculatory ducts extend vertically towards 

 the urethra. It is between and behind the lateral lobes and this 

 part of the gland is distinctly separated from the lateral lobes by 

 a thick layer of connective tissue (fig. 7). This lobe in the series 

 under consideration is made up of nine branching tubules of large 

 size whose ducts communicate with the urethra on its floor or 

 posterior wall outerward from the openings of the ejaculatory 

 ducts and at no point do any of the branches of these tubules 

 intermingle with the tubules of the lateral lobes, being in all 

 places separated from them by a definite layer of connective tissue. 

 In the apex of the gland some of these tubules send branches 

 forward or outward but elsewhere they extend in a bladderward 

 direction. 



The comparative decrease in size of the tubules of the anterior 

 lobe noted in the prostate of the twenty-two weeks old fetus is 

 also striking in this series. The number of tubules making up the 

 anterior lobe noted in the fetuses younger than twenty-two weeks 

 was about twice as great as that noted in the specimens twenty- 



