. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MARSUPIALI A. 313 lateral and posterior part of the penis, until it is inserted with the opposite muscle at the base of the glans. In the Opossum and those Marsupials which, having a bifid glans, enjoy, as it were, a double coitus, there is a levator penis (f, J\ fig. 136), which is not present in the Kangaroo. Each portion of this muscle takes its origin from the fascia covering the crus penis, con- verges towards its fellow above the dorsum penis, diminishing as it converges, and termi- nates in a common tendon inserte
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. MARSUPIALI A. 313 lateral and posterior part of the penis, until it is inserted with the opposite muscle at the base of the glans. In the Opossum and those Marsupials which, having a bifid glans, enjoy, as it were, a double coitus, there is a levator penis (f, J\ fig. 136), which is not present in the Kangaroo. Each portion of this muscle takes its origin from the fascia covering the crus penis, con- verges towards its fellow above the dorsum penis, diminishing as it converges, and termi- nates in a common tendon inserted into the upper part of the base of the glans. There is another powerful muscle which, though not immediately attached to the penis, must exert, in all Marsupials, so important an influence upon its erection as to merit notice here. This is the external sphincter ani, or more properly ' sphincter cloacae :' it is an inch and a half in breadth in the Kangaroo and half an inch in thickness; from the back of the termination of the rectum it passes over the anal glands and sides of the base of the penis, inclosing the two bulbs with Cowper's glands and their muscles, and terminates anteriorly in a strong fascia above the dorsum penis, so as to compress against that part the venae dor- sales. This adjustment and function of the great sphincter did not escape the observation of Cowper. Speaking of the erectores penis of the Opossum, he says, " the muscles of the cavernous bodies of the penis of this creature, having no connexion with the os pubis, cannot apply the dorsum penis to the last-named bone and compress the vein of the penis, whereby to retard the refluent blood and cause an erec- tion, as we have observed in other creatures; but some large veins of the penis here take a different course, and pass through the middle parts of the bulb (crus), and are only liable to the compression made by the intumescence of the muscles (c c) that inclose them. But the chief agent in c
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