280 



DISSECTION OF THE ABDOMEN. 



it (tunica 

 vasculosa). 



Secreting 

 tubules : 



appearance 

 and 



length ; 



communi- 

 cations ; 



and size. 



Tubes 



change their 

 name. 



They form 

 the lobes : 



number ; 

 shape ; 



tubes in 

 them, and 

 arrange- 

 ment. 



Tubes next 



become 



straight 



(tubuli 



recti), 



afterwards 

 join toge- 

 ther (rete 

 testis), 



and leave 

 the gland 

 as vasa 

 efferentia. 



vasculosa, which lines the fibrous coat, and covers the different septa 

 in the interior of the gland. It is formed of the ramifications of 

 the blood-vessels, united by areolar tissue, like the pia mater of 

 the brain : in it the arteries are subdivided before they are dis- 

 tributed on the secreting tubes and the small veins are collected 

 into larger trunks. 



The seminal tubes (tubuli seminiferi) are very convoluted, and 

 are but slightly held together by fine areolar tissue and surrounding 

 blood-vessels, so that they may be readily drawn out of the testis 

 for some distance : their length is about two feet and a quarter 

 (Lauth). Within the lobes of the testis some tubes end in distinct 

 closed extremities ; but the rest communicate, forming loops or 

 arches. Their diameter varies from T ^th to T ^th of an inch. 

 The wall of the tube is formed of a thin translucent membrane, but 

 it has considerable strength. 



Names of the different parts of the tubes. To different parts of the 

 seminal tubes, the following names have been applied. Where the 

 tubules are collected into masses, they form the lobes of the testis. 

 As they enter the fibrous mediastinum they become straight, and 

 are named tubuli recti. Communicating in the mediastinum they 

 produce the rete testis. And, lastly, as they leave the upper end 

 of the gland they are convoluted, and are called vasa efferentia, or 

 coni vasculosi. 



The lobes of the testis (fig. 104, a) are formed by bundles of the 

 seminiferous tubes, and are situate in the intervals between the 

 processes of the tunica albuginea. From 100 to 200 in number 

 (Krause), they are conical in form, with the base of each at the 

 circumference, and the apex at the mediastinum testis ; and those 

 in the centre of the testicle are the largest. 



Each is made up of two or more tortuous seminal tubules ; and 

 the minute tubes in one lobe are united with those in the neighbour- 

 ing lobes. Towards the apex of each lobe the tubules become less 

 bent, and are united together ; and the tubuli of the several lobes 

 are farther joined at the same spot into the tubuli recti. 



Tubuli recti (fig. 104, c). The seminal tubes uniting together 

 become narrower and straighter in direction, and are named tubuli 

 recti or vasa recta : they pierce the fibrous mediastinum and enter 

 the rete testis. 



Rete testis (fig. 104, e]. In the mediastinum the seminal tubes have 

 no proper walls (beyond epithelium), and are situate in the anterior 

 part, in front of the blood-vessels ; they communicate freely so as to 

 form a network. 



Vasa efferentia (fig. 104, /). From twelve to twenty tubes leave 

 the top of the rete, and issue from the upper end of the testicle 

 as the vasa efferentia : these are larger than the tubes with which 

 they are continuous, and end in the canal of the epididymis (part of 

 the common excretory duct). Though straight at first, they soon 

 become convoluted, and form the coni vasculosi. In the natural state 

 the coni are about half an inch in length, but when unravelled the 



