DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 571 
cular fibres covering the whole length of its exterior. This is the true compressor 
urethre ; and, as far as my dissection enables me to judge, the muscular sheet in question 
comprehends what, in human anatomy, have been respectively termed the circular jibres 
of Santorini, or stratum internum circulare of J. Miiller, the constrictor urethre, and the 
levator prostate. The compressor urethra, then, in Otaria jubata embraces the membra- 
nous portion of the urethra in such a way that it appears to surround the parts spirally. 
The fibres posteriorly are partially continuous with those of what has been named by 
some anatomists the “ sphincter vesicw.” ‘They are very sparse over the prostate, how- 
ever, and, on reaching the membranous portion of the urethra, apparently divide into 
two thick symmetrical halves, which have a direction downwards and forwards towards 
the anus and pubes. These fleshy moieties may be taken as the equivalent of Guthrie’s 
muscle in the human being, which would seem to be but the continuation forwards of 
the outer oblique fibres of the bladder, Pettigrew’s figure-of-8 loops. In front and 
below, a laterally compressed band of fibres goes towards, and joins, through the recto- 
vesical fascia, the levator ani muscle. ‘This portion seems to represent the “levator 
prostate” of Santorini, Albinus, and Soemmering, and to be the fibres known as Wilson’s 
muscle. Some few fibres, again, extend upwards to the symphysis pubis; these are 
analogous to the constrictor urethre of some human anatomists, and may be what has 
been described as the ascending portion and origin of Wilson’s muscle. 
The bulbo-cavernosus muscle is made up of strong fibres, which curve round the bulb 
as in other Carnivora &c. The erectors of the penis have origin from the ischial 
tuberosities ; and each, as a thick carneous mass curvilinear in figure, is inserted into the 
side and postero-inferior surface of the enlarged crus penis. 
The sphincter ani internus is strong and broad. It powerfully constricts the lower 
part of therrectum and anus for an inch or more. The circular fibres join those of the 
transversus perinzi, levator ani, and retractores penis. There is also an external sphincter 
of the anus, which is of considerable size. 
Reference and figures of the unusually large and peculiarly inserted levator ani and 
transversus perini muscles are given in Part II.; so that nothing further need be said 
of them in this place. 
c. 3 Genital Glands, Scrotum, &c.—Prostate gland.—Surrounding the urethra for 
an inch in antero-posterior extent, and of a cylindroid or spindle-shape, is the very 
moderately raised glandular body of the prostate. Its structure is compact and finely 
textural, merging almost indefinitely in the fibres of the sphincter vesice behind, and 
equally continuous with the urethral walls in front. The efferent canal and ejaculatory 
ducts appear to open at the minute orifice of the sinus pocularis an inch in advance of 
the apertures of the ureters. 
There are no vesicule seminales; and bodies representing Cowper's glands are absent, 
or so small as to escape observation. 
Testes and surrounding parts.—Enyeloped in a strong, but loose, tunica vaginalis, the 
