302 OSWALD S. LOWSLEY 



develop at the middle of the fifth month. Pallin, on the other 

 hand, found the musculature to be developing at the fourth 

 month. 



Albarran 9 describes a group of glands under the neck of the 

 bladder which open into the urethra and whose tubules lie between 

 the mucosa and the musculature. He calls this the subcervical 

 glandular group and states that it varies greatly in different indi- 

 viduals and may be entirely lacking in some. 



The bladder, trigonum vesicae, and internal sphincter have 

 received a great deal of attention by writers on the anatomy of 

 this region. 



J. Griffiths 10 believed the trigonum vesicae to be composed 

 only of the innermost bands of muscular bundles of the bladder 

 wall, while the outermost longitudinal bundles pass on to the 

 neck of the bladder. 



W. Waldeyer 11 called attention to the following facts in regard 

 to the trigonum vesicae: (1) There is a separate development of 

 its musculature which is continuous with the musculature of the 

 ureters and the prostatic urethra. (2) There is an absence of a 

 submucosa over the trigone. (3) It has a smooth, firm, thick 

 layered mucous membrane. 



Versari 12 concludes from his studies that normally the muscula- 

 ture of the trigonum vesicae is made up of (a) the trigonal portion 

 of the internal sphincter, (b) part of the muscular layer of the ure- 

 ters, and (c) the muscle bundles of their sheaths. In adults there 

 are present in the trigonal region bundles which come from the 

 muscular layer of the bladder. 



Walker 13 agrees with the above findings in part. He observes 

 that from the ureter on each side a thick band of muscle passes 

 down towards the urethra. These bands converge and unite 

 so that this longitudinal muscle flows over the margin of the ure- 

 thral opening in a continuous sheet. In the center of the triangle 



!l Albarran, Maladies de la prostate, p. 526, 1902. 



10 J. Griffiths, Jour, of Anatomy and Physiology, 1891, p. 535. 



11 W. Waldeyer, Das Trigonum Vesicae, Sitzungsberichte der akadamie der Wis- 

 senschaften in Berlin, 1897, p. 732. 



12 Versari, Ric. d. Lab. d. Roma, vol. 13, 1907. 



13 Walker, Jour, of Anatomy and Physiology, vol. 40, p. 190, 190G. 



