6

also a pair of retractores' arising from the os coccygis, fig. 522, P, q, passing on each side the sphincter ani, r, then converging to run together along the urethral side of the penis, s, to the base of the prepuce. In the castrate horse these usually degenerate into elastic sclerous tissue.

§ 378. In Artiodactyla.-The male organs of the Suide are chiefly remarkable for the enormous development of the Cow

perian glands. The testes are perinæal: the scrotum slightly projects; it is not pendulous. The vesicular glands are large, lobulated, with parenchymatous walls, their ducts terminate distinctly from those of the testes. The prostates are small, near the cervix of the vesiculæ. The muscular part of the urethra is of great length and the Cowperian glands are co-extended therewith each presents an elongate subtrihedral form, invested by a muscular capsule; the glandular parietes are very thick:

the terminal duct opens beyond a transverse valvular fold separating the bulbous from the muscular part of the urethral canal. The penis shows a sigmoid flexure, and has a pair of 'retractores,' arising from the hollow of the caudal end of the sacrum, and inserted at the end of

the bend next the glans. This is triquetral, elongate and pointed. The spongy part of the urethra, between glans and bulb, is reduced to a few veins. The preputial opening is near the navel.

524

Suspensory ligaments and muscles of penis, Horse.

The Ruminant Artiodactyles are devoid of vesicular glands; their testes pass into a pedunculate scrotum. The spermatic arteries form, by their close and numerous convolutions, a plexiform mass, which is specially notable in the Bull. The vasa deferentia slightly enlarge at their termination in the Camel, but are not there different in structure from the rest of the sperm-ducts: they terminate upon a broad wrinkled verumontanum. The prostate is a transversely oblong compact body with a smooth exterior, the secretion passes by several orifices into the depressions at the sides of the verumontanum. Cowper's glands are of moderate size, subcircular, compact in structure, with a thick muscular capsule. The corpus spongiosum commences by a plexus of veins affecting a parallel course around the membranous part of the urethra, but convolute in diverse directions to form the bulbous expansion; advancing from which the veins become reduced to two or three in number, running parallel with each other and the urethra. The cavernous part of the penis forms a slender cylinder, it extends forward beneath the linea alba, closely connected therewith, making a ridge along that part of the abdominal surface; then becoming free and receiving a reflected covering of skin, or prepuce,' anterior to which usually depends a tuft of hair. The glans, in the Camel, is long, pointed, with its apex continued beyond the urethral opening and bent back.

In the Goat, fig. 525, the dilated terminal parts of the spermducts, a, a, have a glandular thickening of the inner tunic. The

prostates, b, b, have each a small central cavity; whence the duct is continued to terminate near the sperm-duct, in an oblong depression by the side of the verumontanum: on a small fold of

this part is the orifice of the protometra which is continued, at

e

526

c, between the dilated sperm-ducts, closely attached thereto by areolar tissue; then dividing into two horns diverging and closely apposed to the sperm-ducts, a, a, as far as the epididymis, in which they are lost. The Cowperian glands, two on each side, open upon the margin of a fold at the bulb of the urethra. The prostatic glands in the Deer, fig. 526, b, b, are more slender in proportion to their length than in the Goat. The protometra, c, is reduced to a hardly distinguishable trace; and its cavity, which exists in the embryo, is obliterated at birth.

In the Bull the narrow elongate prostates are irregularly contorted. The erectores' and acceleratores' are powerful muscles. The slender retractores' arise from the anterior commissure of the sphincter ani. Prostates and protometra, Deer. There are preputial follicles in most Ruminants, especially the Antelopes; but only in the Muskdeer do they attain the size and structure described in the preceding chapter. In no hoofed Mammal is there an 'os penis.' § 379. In Carnivora.-The outward indications of the male sex

:

are hardly distinguishable in the Seal tribe. Here, the testes, when extra-abdominal, make no scrotal projection: they are imbedded in areolar tissue, between the pubis and the thighs the tunica vaginalis communicates freely with the abdomen: the sperm-ducts take the usual course. There are no vesicular glands; there is but a small subbilobed prostate. The penis makes no outward projection: the preputial opening, about six inches in advance of the vent, is inconspicuous. The glans penis is pointed, supported by a bone about half an inch long, in Phoca vitulina, into which are inserted a pair of 'retractores,' arising from the anterior commissure of the anal sphincter. The remnant of the protometra in Ph. vitulina, is but two lines in length; the orifice behind the verumontanum is rarely patent. The os penis of the Walrus is a massive subcylindrical bone, sometimes two feet in length, expanded at one end, where the cancellous structure prevails.1

The testes lie under the skin of the groin in otters, under that of the perinæum in civets. The scrotum, where best developed in Carnivora, is hairy and less pendulous than in Ruminants. As in these, the vesicular glands are absent; the prostatic glands are small and compact. The penis, save in Canida, Viverrida, and Hyana, has a bone.

527

a

In the Bear the sperm-ducts are enlarged and in close contact at their terminations, with thick follicular walls beyond this glandular part they retain their width, but contract to open upon the verumontanum.3 A thin layer of prostatic substance surrounds the beginning of the urethra. The os penis in Ursus arctos may be 6 inches in length. In the Subursine genus Meles a remnant of the protometra, fig. 527, a, rises between the glandular ends of the sperm-ducts, b, b: its cornua are reduced to mere filaments, c: the prostate is better developed than in Ursines, especially in the Racoon, in which it is in advance of the neck of the bladder. In the Kinkajou the os penis is sub-bifurcate at the distal end, which is covered, as in most Subursines and Mustelines, by the membranes of large dilaXLIV. p. 638, No. 3919.

Protometra, a, nat. size,
Badger. CCXXXIX".

2 Les vésicules séminales existent dans les coatis,' xII. tom. viii. p. 160. Hunter, however, expressly affirms of his Swash,' which I determined by the skull (No. 4669, XLIV.) to be a young Coatimondi, that it has no vesiculæ seminales.' ccxxxvI. vol. ii. p. 90. The same result has been had from subsequent dissections at the Zoological Gardens. CCLXXIII".

4 A fossil specimen of this bone, in Ursus spelaus, measured nine inches.

table sinuses, and projects beyond the proper erectile tissue of the glans. Besides the usual muscles of the penis there is, in Plantigrades, a pair arising from the sacrum diverging to include the sphincter ani, and then continued on to the dorsum penis as far as the bone. In the Otter the sperm-ducts have glandular terminations. Between the two there is a small body or canal which enters the urethra at the caput gallinaginis, but not with the vasa deferentia:' in this remnant of the protometra the cornua are filamentary, as in Meles. In Mustela martes, also, Hunter observes: There is a small cavity between the two vasa deferentia, at their entrance into the urethra, which will admit the small end of a small blow-pipe; but I could not find any natural opening into the urethra.'2

In the Dog-tribe the scrotum is more prominent than in Mustelines or Plantigrades. The prostates form a protuberant body, and exude the secretion by several pores at the sides of the verumontanum. The spongy tissue of the urethra expands suddenly and considerably at the base of the glans, which has an ossicle: the blood is thence returned by two venæ dorsales penis': these are compressed by the action of levatores,' arising from the first caudal vertebra, passing one on each side of the anal sphincter, then converging to gain the dorsum penis, crossing the veins, and terminating at the base of the bulbous part of the glans. As long as the levatores' retain the stimulus to contract, after coition, the distended glans forms a mechanical impediment to retraction of the penis from the vagina.3 The ossicle is grooved for the urethra.

The prostates are moderately large and lobulate in the Ichneumons, in which Cowperian glands also exist. In the Suricate (Rhyzana tetradactyla) the scrotum is as little marked as in Mustelines: there are neither vesicular nor prostatic glands; but there is a pair of very large Cowperian glands, with the usual muscular capsule, and with unusually long ducts, through which the secretion is propelled to a dilatation near the distal end of the urethra: behind their orifices a semilunar fold opposes the retrograde passage of the secretion into the long tract of urethra intervening between it and the neck of the bladder. In the Zibet (Viverra Zibetha) there is a small prostate: beyond

' ccxxxvi. vol. ii. p. 74. See also CCXLI”. p. 49.

I laid bare the penis of a dog, almost through its whole length; traced the two veins that came from the glans and separated them from the arteries by dissection, that I might be able to compress them without affecting the arteries. I then compressed the two veins, and found the glans and large bulb became full and extended.' XCIV. p. 32.