vena dorsalis, and more deeply excavated below for the corpus spongiosum urethræ.1

§ 375. In Sirenia.-These mutilate Mammals are also testiconda,' but differ from the Cetacea in having vesicular glands, a penis with a septum corporis cavernosi,' and provided with a pair of levatores,' which unite to form a tendon upon the dorsum.' In the Dugong (Halicore), the glans consists of two semilunar side-lobes, including the conical process, on the apex of which the urethra opens. In a half-grown male the vesicular glands were four inches long and two inches across the fundus, where their glandular parietes were thickest; the internal surface was reticulate. The vasa deferentia were irregularly convoluted: they communicated with the duct of the vesicular gland, the common opening being into the dilated beginning of the urethra, which describes a curve below the vesical orifice: according to Leuckart, it receives the opening of a bottle-shaped protometra, about an inch in length.2

§ 376. In Proboscidia.-The testes retain in the Elephant the situation in which they were developed, viz. below or beyond the kidneys. Their ducts have the same minor degree of density as in Sirenia and other testiconda;' they describe a tortuous course to between the urinary bladder and vesicular gland, where they terminate on a papillary eminence at the fundus of a true seminal bladder, of a pyriform shape, with thin walls and a smooth internal surface. These terminal reservoirs are in contact and adherent: they open into the beginning of the urethra distinctly from the orifices of the vesicular glands. These are elongated and rather contracted toward the closed end, which is divided by a constriction or septum from the general cavity, with which it communicates by a small canal. The glandular parietes are thickest at the closed end, and the inner surface is broken by decussating columnar processes projecting into the cavity; their interspaces extend in many parts, like sinuses, deep into the substance of the vesicular walls: towards the urethra these walls become smoother. Each vesicle has a special muscular investment, for expulsion of its secretion into the urethra. The prostatic glands are two on each side, external to the vesicular ones, and of much smaller size: they are also provided with a partial muscular covering. A cæcal rudiment of the protometra extends from the base of the verumontanal cul-de-sac. The corpora cavernosa penis are divided by a thick sclerous vertical partition, and in transverse section present a reniform figure, with 2 ccxxxix". p. 1429.

1

XII. vol. iv. p. 87, No. 2527.

the corpus spongiosum and urethra occupying the concavity. The veins of the corpus cavernosum are surrounded by a soft tissue of unstriped muscular fibre. The glans penis is elongate, subcylindric at the base, becoming rather depressed at the end, which is obtuse and rounded. Besides the ordinary muscles, there are a pair of levatores penis,' arising from the pubis, sending their tendons into the dorsum, where they coalesce above the vena dorsalis, and run along a sheath of the thick sclerous wall to the glans.

6

519

§ 377. In Perissodactyla.--In the Rhinoceros the testes are inguinal, in close contact with the abdominal rings. The tunica vaginalis communicates freely with the peritoneal cavity. The testis is surrounded by a strong and thick tunica albuginea:' the 'corpus Highmorianum' is continued in the form of a moderately thick white band, from the end where the efferent vessels pass out to form the caput epididymidis,' along the whole longitudinal axis of the gland. From this band or centre of the cellular framework of the gland, the septal layers diverge to all parts of the external tunic, forming the compartments in which the lobes of aggregated tubuli seminiferi' are lodged. The branches of the spermatic artery, on penetrating the tunica albuginea, pass directly to the corpus Highmorianum, and their ramifications diverge thence, supported by the radiating septa, and form a rich network upon the inner or vascular layer of the capsule of the testis. The vas deferens in the inguinal canal is surrounded by the vessels and especially by the plexiform veins of the spermatic chord; on entering the abdomen it is received in a peritoneal fold, and is conducted to the side and then to the back part of the urinary bladder, passing between the bladder and the ureter: having got to the inner side of the termination of the ureter, fig. 519, u, the vasa deferentia, ib. vd, descend straight, slightly converging, to the middle of the back part of the prostate, p: they penetrate that gland, together with the ducts of the vesicular glands, vs, lying to the inner side of these; and, communicating with them, the common duct

on each side finally terminates by a minute pore upon the crucial verumontanum. The vasa deferentia are thickened to about thrice their ordinary diameter in the last three inches of their course;

521

but their canal or area is not proportionally

dilated; it is, on the contrary, rather contracted, by the thickness of the cellulo-glandular parietes to which the enlargement of the duct is due. The vesicular glands, ib. rs, present an elongate subcompressed pyriform shape, eight inches in length, and three inches and a half across the broadest part of the fundus. They have a lobulated exterior, and a structure very similar to that of the same bodies in Man. The prostate, ib. p, resembles that of many Rodents, being composed of an aggregate of long slender cæcal tubes with glandular walls converging to the ducts of the vesiculæ and vasa deferentia, and opening by numerous minute apertures on the verumontanum. The breadth of the prostate is six inches; its antero-posterior extent four inches: it does not quite surround the beginning of the urethra, but is closely applied to the back and sides of that canal. The muscular part of the urethra extends about three inches from the prostate

C, c.

before it joins the bulbous and cavernous portions, close to which are situated two large subcompressed oval Cowperian glands, ib. Each of these measures three inches and a half by two inches and a half. The great plexus of veins above the dorsum penis, near its root, is enveloped in a mass of elastic tissue, u like the dartos' of the human scrotum.

6

The fleshy part of the 'levatores penis,' fig. 520, 1, 1, measures fourteen inches in length, five inches across their basal origin, and between one and two inches in thickness. Their oblique origin is extended over the space of one foot from the ento-pelvic part of the pubis down to the ischium. The tendinous part of the muscle commences where the pubic portion joins the ischial one at the inner and under border of the fleshy part:

it is half an inch thick at its commencement, but expands as it extends along the muscle, the fleshy fasciculi of which are inserted into the tendon in an obliquely converging, or semipeuniform manner. As the tendon augments in breadth, it diminishes in thickness, converging towards its fellow, which it meets and joins two inches before the anterior termination of the fleshy portion. The two united flattened tendons beyond are gradually converted into a round chord of ligamentous substance an inch in diameter. This chord, ib. I, l', glides through a strong slightly elastic aponeurotic sheath, along the median groove of the dorsum penis; it is connected with the inner surface of the sheath by a highly elastic cellular tissue; the chord maintains its ropelike character along the basal third of the glans, then subsides, expanding laterally, and is finally lost upon the firm capsule of the glans. There is no os penis.' A pair of 'retractores penis,' fig. 520, t, t, are inserted into the under part of the base of the glans. The nerves of the dorsum penis, the arteries, and trunks of two large plexuses of veins, pass beneath the bridge formed by the confluence of the tendinous and muscular parts of the levatores penis' and between the two suspensory ligaments of the penis. These ligaments are an inch in breadth, and onethird of an inch in thickness at their origin from the ischio-pubic arch a little in advance of the ligamentous attachments of the crura corporis cavernosi. The total length of the undistended penis is three feet nine inches; the circumference of the prepuce is one foot five inches. The preputial orifice is two feet ten inches from the vent. The substance of the large reflected preputial fold of soft integument, fig. 520, p, r, is from half an inch to two-thirds of an inch in thickness, and consists of a moderately compact cellular corium, with a delicate epiderm, minutely rugose, in the transverse direction, and perforate or punctate with the pores of the mucous follicles which are very regularly dispersed at intervals of about a quarter of an inch. The glans penis, ib. gl, is a long and slender subcompressed cone with a truncate apex ; in its flaccid undistended state, it is one foot in length: the prepuce is reflected upon its base at the same transverse or circular line, and there is no frænum. The apex, ib. a, is not simple, but resembles a mushroom on a thick peduncle, fig. 521, l, projecting from an excavation at the end of the glans with a thin wall or border, ib. e, e, like a second prepuce; but this is of the same structure as the rest of the firm surface of the glans. of the base of the glans, and rather towards its under part, there

On each side

is a longitudinal thick oblong ridge or lobe, fig. 520, r, three inches and a half in length, and eight lines in basal thickness: the thick rounded free border of each lobe inclines downwards. A narrow ridge commences in the median space of the dorsum glandis,' which increases in height as it advances forwards, and then subsides two inches from the border of the terminal or apical fossa. The projecting border of this fossa describes a compressed oval, and is attached to the pedunculated appendage, fig. 521, a, by a process, like a frænum, continued upon the middle line of both the upper and under surfaces, ib. f, of the thick peduncle: the fossa between this peduncle and the free external border is two inches in depth. The stem, l, of the terminal expanded discoid appendage is subcompressed with an oval section: the disc is ovate, one inch eight lines long by one inch across its broader inferior part, where it extends farthest from the supporting stem. The urethra, u, terminates in the middle line of the disc between its middle and upper third.

In the Sumatran Tapir the base of the glans has an upper lobe as well as one on each side, beyond which it is continued forward contracting, but terminates in a truncate surface on the middle of which the urethra opens. In the American Tapir the orifice is nearer the lower margin of the disc. The testes are inguinal, in a slightly indurated sessile scrotum, about 6 inches below the vent. The accessory glands resemble those of the Rhinoceros.

The testes were abdominal, below or beyond the kidneys, in the Hyrax (H. capensis) dissected by me: the vasa deferentia are convoluted, like a second epididymis, behind the urinary bladder: they terminate near to, but distinct from, the ducts of the vesicular glands, at the lower end of the unusually elongated muscular tract of the urethra: the vesicular glands extend on each side of this canal, their closed ends just reaching the bladder. Two prostates, of a tubular structure, are near the duct-ends of the vesicula. Two small flattened Cowperian glands communicate by long ducts with the wide cavity of the bulb of the urethra. The penis is bent abruptly backward, and the glans has a truncate termination. Besides the erectores' and acceleratores,' there is a pair of levatores,' arising from the symphysis pubis, and terminating by a single tendon, as in the Rhino

ceros.

In the Horse the scrotum, fig. 522, a, is suspended between the thighs at a distance of about nine inches beneath the anus, whence