the abdomen is easy. The epididymis, after quitting the testis,

recedes, and is connected therewith for the rest of its extent by a fold of serous membrane. The prostatic glands are large and ramified, one on each side the muscular part of the urethra, with which they communicate close to the verumontanum: the terminal orifices of the vesicular glands are wider. The levator penis is inserted into an ossicle in the glans. The penial bone is strong in the Capybara: the vesicular glands in that Rodent are long and large, slightly branched: the prostatic glands are short, broad, and thick, consisting of numerous slender ramified cæca.

506

In the Agouti and Acuchi (Dasyprocta) the testes, during the rut, lie in the perinæum, one on each side the retroverted bend of the penis; the cremaster is a sacciform development of the inferior fibres of the obliquus internus abdominis, which is inverted when the testes return to the abdomen. Adipose appendages extend from the spermatic cords. The vasa deferentia, fig. 506, c, c, have usually a tortuous course behind the bladder: they terminate in the urethra distinct from the ducts of the vesicular glands, ib. k, k: these bodies, i, i, are long and ramified; the style, 1, m, indicates the urethral end of the duct. The prostatic glands, e, e, are shorter, and consist of a fascicule of slender cæca, which unite and form the short duct through which the style, g, k, passes. The Cowperian glands, ib. o, o, are of a compact oval form, and send their secretion by a short duct, traversed by p, q, into the bulbous part of the urethra. The bulb is compressed by its acceleratores:' the cavernous crura of the penis by the erectores: the 'levatores penis,' which unbend the organ during erection and compress the venæ dorsales penis,' rise from the symphysis pubis, and send their tendon along the dorsum to be inserted into the ossicle of the glans. This part is provided with a pair of lateral dentate horny plates, ib. b, b.

6

Male organs, Agouti, CXXII'.

In the Guinea-pig (Cavia cobaya), the os penis' is a flat and slightly curved bone imbedded in the upper part, and reaching as far as the extremity of the glans above the canal of the urethra. Behind and below the termination of the urethral canal is a wide pouch, in the bottom of which are lodged two horny styles. This pouch, during erection, is everted, so that the horns protrude externally. Two tendons are connected with the bottom of this pouch, which run along the penis inferiorly, and come from a thin layer of muscular fibres, derived from the erectores they invert the pouch and draw it back again within the glans. The surface of the glans is beset with corneous scales. This singular armature of the intromittent organ is maximised in the spotted Cavy (Calogenys subfuscus), of which, fig. 507 shows the glans beset with short spines, the long terminal horny spikes, and the lateral horny plates, with marginal retroverted serrations.

507

In Capromys I found a large adipose appendage attached to the epididymis. The ducts of the seminal, vesicular and prostatic glands terminate by distinct orifices; the fossa receiving those of the right side being divided by the verumontanum from the left one. The protometra is reduced to a small cul-de-sac behind the neck of the bladder; it seems like a blind backward continuation of the urethra separated by a transverse ridge from the orifice of the bladder. The vesicular glands present a white and glistening exterior; they are of an elongated form, with thin parietes, and send off, on one side principally, from fifteen to twenty obtuse cæcal processes. The prostate gland consists of four principal masses or lobes, each composed of a number of flattened tubular cæca, with thin and easily lacerable parietes, compacted together by cellular tissue. The muscular part of the urethra is closely embraced by a thick stratum of muscular fibres, diverging in a double oblique or penniform manner from a middle longitudinal inferior raphe: the acceleratores urine' have the usual relations to a large bulb of the urethra: the crura penis are embraced by short but strong erectores;' the 'levatores' muscles, or compressores venæ dorsalis,' terminate in a single tendon, passing along the dorsum penis, to be inserted into an elongated flattened ossicle in the glans, which, in this genus, is

6

xx. vol. iv. p. 75, Nos. 2495, 2496.

unprovided with the horny armature which gives it so remarkable a character in the Cavies.

In the Beaver (Castor canadensis) I have usually found the testes, fig, 508, r, s, though small in proportion to the bulk of the animal, lodged in subcutaneous depressions between the castor-bags; but with the usual wide opening of the tunica vaginalis,' permitting easy re

508

turn of the gland into the abdomen. The tortuous disposition of the vasa deferentia would favour such periodical movements of the testes: the terminal portion of the ducts, fig. 508, a, is dilated, or enlarged by glandular thickening of the walls, the inner surface of which is multiplicate. The vesicular glands are (for Rodents) moderate sized convoluted bags, fig. 508, o, p: the duct, fig. 509, d, sometimes communicates with, sometimes terminates distinctly from, the contiguous vas deferens, ib. a. The prostatic glands, ib. c, c, are a cluster of shorter pyriform sacs, the long slender ducts of which intercommunicate before terminating in the urethra. The protometra, ib. b, b, soon divides, after its communication with the urethra, into two longcornua,' which lie on the peritoneal fold behind the neck of the bladder, mesiad of the vasa deferentia, the course of which they follow till they become too attenuated for distinction. The Cowperian glands, fig. 508, m, n, are of a compact oval form, situated between the erectores' and acceleratores' muscles; and opening into the bulb of the urethra. The maximised preputial glands, ib. e, f, and ano-preputial glands, g, k, h, i, have already been described.

6

6

In the Water-vole (Arvicola amphibia) the epididymis, fig. 510, f, g, is connected by longer vasa efferentia' than usual with the testes, ib. c, d. The vesicular glands, ib. k, l, relatively larger than in Castor, are bent upon themselves, and subdivided along one border each prostate consists of three lobes, ib. m-r, or

aggregate groups of cæca. The Cowperian glands resemble those of Castor. A pair of long thin glandular bodies opening into the prepuce, on each side the glans, ib. a, answer to the chief castor-bags, c, f, fig. 607, in the Beaver: the homologues of g-k, fig. 508, are confluent and surround the termination, fig. 510, v,

Protometra and prostates, Beaver. (Part of Pl. vi. ccxXXVIII")

of the rectum s, and exude their opaque the anus.

whitish secretion near

In the Marmots (Arctomys) the preputial orifice is more distinct than in most Rodents from that of the rectum: in the Alpine marmot the space of an inch intervenes. The prostates form a considerable mass, aggregated into two roundish lobes. The mesorchial accumulation of fat is considerable at the commencement of hibernation. The vesicular glands of the Jerboa (Dipus sagitta) resemble those of the Vole, but are less notched. In Helamys capensis, they consist of slightly sacculate pendulous bags, with thin walls: the prostatic follicles are numerous, short, and thick: the glans penis becomes singularly expanded, and forms a hollow disc in the centre of which opens the urethra.

In the Rat and Mouse the periodical enlargement of the testes,

510

fig. 511, c, is considerable': the globus major of the epididymis lies in the cremasteric pouch, which is inverted when the reduced testis returns into the abdomen. The vasa deferentia, ib. f, receive at their termination the secretion of the small glands with a granulated exterior, e: the vesicular glands,' ib. a, a, are large, lobulate, and exude a hardish cheese-like secretion. The prostatic glands, b, c, are masses of slender subconvolute tubes. The Cowperian glands, of the usual compact form, lie one on each side of the rectum and send their long ducts to the large foramen cæcum' at the urethral bulb. The penis has its levator' muscle and ossicle: the prepuce is served by a pair of glands secreting a whitish

mucus.

The spermatozoa of the Muride have the body' shaped like the bent blade of a knife, when viewed in profile, fig.

Ꮽ

Male organs, Water-vole. CXXII'.

512, A, B; the vibratile 'tail' is very long: in the Squirrel (fig. 513) the body is lamelliform, with the surfaces subbiconcave, and

the margin thickened an

teriorly the tail' is of moderate length. It is relatively shorter to the body in the Guinea-pig, fig. 514,d: in this figure a portion of a tubule of the testis is magnified 300 diameters, showing the basilemma a, a, its lining(precipitate) of nucleate corpuscles and granules, b: with the developed nuclei of detached cells, forming the spermatozoa, a.

511

a

Male organs, Rat.

$372. In Insectivora. - The periodical enlargement and 'As in birds; see vol. ii. p. 243, and xx. vol. iv p 79.