STRUCTURE OF COATS OF TESTIS. 133 



closed tubules the two extremities of which are dilated, and 

 which lies between the head of the epididymis and the vas 

 deferens, is perhaps analogous to the Parovarium, and to be 

 regarded as the remains of the Wolffian body. 



The Tunica albuginea, or fibrous investment of the testis, 

 is formed of connective tissue with a sparing quantity of delicate 

 elastic fibres; its thickness increases towards the posterior 

 border, where it penetrates into the interior of the gland as 

 the mediastinum testis, or corpus Highmori. In addition to 

 this, it sends off from every part of its internal surface, besides 

 isolated fasciculi of connective tissue, flat processes, the septula 

 testis, which run towards the mediastinum. 



The parietal lamina of the tunica vaginalis propria, like 

 the visceral, is composed of connective tissue traversed by fine 

 elastic fibres, and is lined on its internal surface with a similar 

 flattened epithelium. 



The tunica vaginalis propria is enclosed in a second investment 

 of connective tissue, the tunica vaginalis communis, which 

 becomes denser towards the apex of the testis, but in the 

 upper parts exhibits a loose laminated structure. 



Upon the inner surface of this, between it and the propria, 

 and united to both membranes, Kolliker discovered smooth 

 muscular fibres, which have since been described by Henle as 

 a cremaster internus, and, according to Rouge t,* may be traced 

 upon the septula testis. On its surface the fan-like expansion 

 of the cremaster externus is spread, the fasciculi of which are 

 surrounded by elastic plexuses. According to Rektorzik,-|- it 

 also supports small non- vascular, rounded, and in part pedi- 

 cellate excrescences. The outermost investment of the testis 

 is formed by the scrotum, the subcutaneous cellular tissue of 

 which contains both isolated and plexiform fasciculi of smooth 

 muscles, which, according to Treitz,:}: arise by elastic tendons 

 from the anterior surface of the os pubis, the ligamentum 

 suspensorium penis, and the crural fascia. This tunica 

 dartos, first accurately described by Kolliker, adheres by 



* Comptes Rendus, Tom. iv., p. 902. 



t Wiener Sitzutigsberichte, 1837, p. 154. 



J Prayer Vierteljahrsschrift, 1853, Band i., p. 113. 



