Salivary glands.—The salivary organs are very large. In the flog there are two sublingual glands; one, which is very long and narrow, accompanies the duct of the maxillary gland, and is composed of small lobes of a pale reddish colour ; the orifice of its excretory duct is near that of the maxillary. The second sublingual gland is placed in front of the former, and is of a square form; it discharges its secretion through eight or ten short ducts, which pierce the mucous membrane of the mouth. The ptrotid is large, its duct opening opposite the third molar tooth ; and in addition to these there are the molar glands, which form two elongated tnasses, situated along the alveoli of the superior and inferior molar teeth, and extending forward as far as the canines; these pour their secretion into the mouth through numerous little orifices.
Os hyoides.—The os hyoides in the Elephant has its body or central portion, which resembles a flattened lamina, slightly arched from below upwards, consolidated with ihe posterior corn ua, which divide into two branches as they curve g-ently backwards and inwards. The anterior corn ua articulate with the styloid process of the temporal. In other Pachyderms the general disposition of the hyoid pieces is very similar to the above, but in the lthinoceros their ar rangement approximates what is met with in horned ruminants, the anterior cornua being articulated to the styloid by an intervening osseous piece.
The laryngeal apparatus exhibits nothing extraordinary in its arrangement.
Circulatory and respiratory systems.—The organs of circulation and respiration likewise, in their general arrangement, differ from those of other Mammalia in no irnportant particular. We may, however, notice one or two deviations from the usual type in the origins of the chief venous and arterial trunks.
In the Hyrax the arch of the aorta gives off the arteria innominata, which divides into the right subclavian and the two common carotids, and then a second single trunk, which is the left subclavian.
The Elephant in several points of its economy exhibits retnarkable affinities with the Roden tia, in proof of which the correspondence of the structure of its heart with that of some of the Rodents is very striking. Thus the right auricle receives three venw cavae, a right and a left superior and an inferior, which latter pre sents the usual arrangement. Moreover, the Eustachian valve, which is placed between die orifices of the inferior and left superior cavm, present, in addition to the inferior portion usually met with, the rudiment of a superior division of the valve, extending from the pos terior aspect of the orifice of the superior eava.
A similar arrangement is met with in the Por cupine and other Rodents.
Urinary organs.--lit the young. animals the kidneys are separated into several lobes by very deep sulci, but in the adults this lobulated appearance is in a great degree obliterated. In other respects the renal apparatus, ureters, and bladder have nothing peculiar in their structure or disposition.
Generative organs (male).—In the structure of the external generative apparatus of the male Elephant, the principal feature worthy of remark is the existence of two special muscles destined to the retraction of the organ after.its erection, an arrangement which is frequently rendered necessary in consequence of its enor mous size in that animal, which is stated to be proportionately greater than in any other quad ruped. These muscles arise from the anterior part of the os pubis on each side of the penis, and uniting at a little distance from their origin form a common tendon, which runs in a groove along the dorsurn of the penis to be inserted into the glans. The action of these muscles will of course be to retract the member into its sheath after erection or after the discharge of urine, which requires a kind of semi-erection, precisely as is the case in the IIorse. The other muscles connected with the generative apparatus agree exactly with those met with in the generality of quadrupeds, from which they only differ in size ; these are the acceleratores urine and the transversales perincei.
The corpora cavernosa, besides the mesial tendinous septum between them, are traversed by strong secondary septa derived from the external envelope, which is of great thickness in proportion to the enormous size of the organ.
The verumontanam., the prostates, Cowper's gland, the vasa deferentia, and the vesicala seminales occupy their usual positions, and have nothing remarkable in their structure or ar rangement.
The testes of the Elephant are not contained in any scrotal pouch or even lodged in the groins, as has been asserted by some authors, who have been deceived by the existence of large glandular masses situated in the inguinal regions; but are deeply situated in the abdomen in close contact with the kidneys, to which they are attached by membranous prolongations resembling little omenta ; consequently the vasa deferentia, which are very large and tor tuous, pass immediately to their destination in the commencement of the urethral canal, being closely accompanied by the ureters during the greater part of their course, and lying between those tubes and the rectuin.