572 DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 
testicles occupy the very remarkable ischio-rectal fosse, 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. There 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 perineum. On removal of the integument and a further dissection being 
made (such as is exhibited in fig. 35, pl. Ixxiii:, 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 perinei. 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 perinei, 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 perineum; 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 perinzi, 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 duplicature 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 
