STRUCTURE OF THE PENIS. 309 



VII. PENIS. The albuginea of the corpus cavernosum 

 urethrge, and that of the corpora cavernosa penis, is composed 

 of connective tissue, elastic fibres, and partially of muscular 

 fibres. The former consists of slightly wavy parallel fasciculi 

 of fibres like those of tendinous tissue. 



These fasciculi of connective tissue form a circular layer 

 around the corpus cavernosum urethrse, that is continuous 

 externally with the loose subcutaneous connective tissue. In 

 the erectile bodies of the penis the fasciculi are arranged in 

 two layers, an external longitudinal and an internal circular, 

 though the former only occurs on the upper and lateral peri- 

 phery of each corpus cavernosum, whilst the circular layer is 

 continued to the lower surface, and forms a septum in the 

 median line between the two corpora cavernosa. 



In the newly born child, the thickness of the external 

 longitudinal layer at the root of the penis is 0*31 of a milli- 

 meter ; that of the internal, 0*49 of a millimeter. In the shaft 

 of the organ this proportion is inverted ; the thickness of the 

 external layer being here 0'45 of a millimeter ; that of the 

 internal, 0'26 of a millimeter. Numerous fusiform cells are dis- 

 tributed amongst the fasciculi of the connective tissue. 



The elastic tissue both in the albuginea of the corpora caver- 

 nosa penis and in that of the urethra, forms dense plexuses of 

 delicate fibres, containing oblong nuclei in the new-born child. 

 Another kind of plexus, more or less close and of variable 

 extent, composed of the nucleated cells very similar to those of 

 embryonic tendinous tissue, is also present in the albuginea of 

 the corpora cavernosa, as well as in the loose surrounding tissue. 



Smooth muscular fibres occur, especially in the body of the 

 penis, both in the corpus spongiosum urethrse and in the 

 corpora cavernosa penis. They are most numerous in the 

 former, in which they pursue a circular course, whilst in 

 the latter they are circular in the circular layer, longitudinal 

 in the longitudinal, and where the albuginea consists of only 

 a single layer, exclusively circular. 



Large nerve trunks, composed of medullated fibres, run in 11 

 the loose tissue in immediate contact with the albuginea. In \ 

 the new-born child many of them lie with small bloodvessels 

 close to the albuginea, in oblong spaces filled with lymph 



