572 DE. J. MUEIE ON THE ANATOMY OF THE SEA-LION. 



testicles occupy the very remarkable ischiorectal fossae, and thus, as respects position, 

 differ widely from those of the Earless Seals, whose testes lie in the pubic region, or 

 the groin outside the abdomen. Theie is, moreover, in this Eared Seal {Otaria jubata), 

 as has been mentioned and figured along with the cutaneous parts, an external scrotum ; 

 but it is not usually prominent ; nor does it generally hang downwards, as in other mam- 

 mals. Indeed the superficial scrotal tissues are chiefly distinguished from the neigh- 

 bouring skin by the wrinkling and folds rather than by the dependent nature of 

 the sac. 



On slight pressure being applied above this somewhat rudimentary scrotum, the 

 testicles come down or emerge from the ischio-rectal cavity in which ordinarily they 

 are lodged, and, as they pass into the scrotal sac, dilate it considerably. They do not, 

 however, show a tendency to remain down, but are easily replaced or returned to the 

 ischio-rectal hollow already alluded to. 



This ischio-rectal fossa, wherein each testicle ordinarily lies, is a narrow elongated 

 cavity, between two and three inches deep, the opening of which is to the outer side of 

 the very limited perinseum. On removal of the integument and a further dissection being 

 made (such as is exhibited in fig. 33, pi. lxxiii., of former memoir), the boundaries 

 and general relations of this cavity are unfolded. These are as follows : — Anteriorly or 

 superficially is a somewhat semilunar-shaped fold of strong fibrous tissue, or proper 

 perineal fascia, which is partly continuous with the dartos or scrotal muscular fibres 

 and those of the transversus perinsei. Externally, above and in connexion with this 

 perineal fascia is the oblique sweeping arch or fleshy plane of the gracilis muscle; 

 beneath or deeply, the great broad semimembranosus ; posteriorly and also deeply, or 

 at the bottom of the fossa, the semitendinosus and partly glands and vessels ; inwardly 

 or in the median line, the transversus perinaei, root of the penis, circular fibres of 

 sphincter ani, and the rectum itself. 



The testis itself and investing vaginal tunic is, moreover, supported by fibres which 

 run towards the perinaeum ; and other still more delicate fibres proceed outwards and 

 pass on to the superficies of the muscles of the lower tibial region. Some of the trans- 

 verse layer of fleshy fibres representing transversus perinaei, along with fibrous tissue and 

 fat, constitute a partial protection or anterior wall to this most unusual testicular 

 chamber. 



The body of the testicle, including the epididymis, is smooth-surfaced, and of an 

 oval or almond shape, 1*8 inch long and 0-9 inch broad. A strong duplicative of the 

 tunica vaginalis firmly binds down the testicle to the bottom of the pouch ; the reflec- 

 tion of this, the tunica albuginea, is of considerable thickness. On a vertical median 

 section of the testis being made, the tunica albuginea is seen to dip between the lobes 

 of the glandular substance. At its back part, where covered by the globus major, it is 

 almost a line in depth ; and, in the uninjected condition, at this part it possesses a punc- 

 tate or trabecular arrangement from the intermingled vascular network, the rete or 



