322 OSWALD S. LOWSLEY 



Their development under the floor of the urethra pushes it up into 

 the lumen causing the characteristic semilunar shape of the pros- 

 tatic urethra. The fact that the lumen of the prostatic urethra 

 below the entrance of the ejaculatory ducts is also crescentic 

 in shape is due to the continuance of the muscular fibers that 

 form the coats surrounding the utricle and ejaculatory ducts 

 under the mucosa of the urethra where they finally become lost 

 in the muscle of that structure. 



Fetus 27 cm. long: {thirty weeks) 



Inspection of the bladder of this specimen cut in cross section 

 corroborates the findings already described, the only difference 

 being that the muscle bundles seem to be larger in this than in 

 any of those previously observed. The trigone is superimposed 

 in the characteristic way and its submucous blood vessels, which 

 in all cases are much more numerous than those of any other por- 

 tion of the viscus, are greatly increased in number and size in 

 this case. The sphincter of the bladder is thicker and composed 

 of heavier muscle fibers than the ones that have been described. 

 Outside of the sphincter are seen the muscle bundles of the vesical 

 wall which become blended with and are lost in the circular fibers 

 forming that structure. 



The subtrigonal glands are present in very small numbers, only 

 four being detected. They extend through the submucous struc- 

 tures and only a very short distance into the musculature of the 

 trigonum vesicae. Their architecture is very slight and there 

 seems to be no particular differentiation of connective tissue or 

 muscle fibers around them. They resemble the urethral glands of 

 Littre more than any other tissue and probably are a continuation 

 upward of those structures. 



The subcervical glands are present in this series, being nine in 

 number. They are all quite small and no branches are noted in 

 any of them. In addition to these nine tubules on the floor of 

 the urethra there are six found on its roof or ventral wall. These 

 tubules are similar in extent and architecture to the subcervical 

 group and are apparently not a continuation upward of the ven- 



