Page:The American Cyclopædia (1879) Volume VI.djvu/526

618 ELEPHANT lished, and the presumption is that she gave him only friendship and poetical sympathy in return for his love. She was never married. ELEPHANT (elephas, Linn.), the only exist- ing representative of the proboscidian pachy- derms, the mammoth or fossil elephant and the mastodon having lived in the preceding geological epoch. The elephant, the largest and heaviest of terrestrial animals, has from time immemorial been celebrated for his in- telligence and sagacity, for the services he has rendered to man in eastern lands, for his im- posing appearance, for his immense strength guided by gentleness and docility, and for the astonishing feats he is able to perform by means of his trunk; Since the time of Cuvier the anatomy of the elephant has been tho- roughly studied. The skull is remarkable for its vertical elevation, giving to the head the well known aspect of sagacity ; this, though far superior to that of the other pachyderms, has doubtless been overrated from the peculiar cranial formation in this animal. The great elevation of the frontal region does not arise from any increase of the cranial cavity or cor- responding development of brain, but depends on the great separation of the tables of the skull, and the excessive enlargement of the frontal sinuses, affording ample space for the origin of the muscles of the trunk ; the upper jaw has a similar structure for the accom- modation of the enormous tusks ; in both cases strength and solidity are obtained without too much weight. The nearly perpendicular facial line of the elephant, then, depends on the size of the frontal sinuses, the shortness of the bones of the nose, and the vertical position of the maxillary and intermaxillary bones; and the cranial cavity occupies but a small part of the head at its posterior central portion. The oc- cipital bone forms the posterior wall of the skull, and advances also on to its upper surface ; the parietals are early consolidated to it, to each other, and to the temporals, forming a solid box ; the ethmoid is large, and the extent and surface of the cribriform plate indicate a delicate organ of smell ; the sphenoid is very flat internally, but its cells are enormously de- veloped, encroaching largely upon the base of the skull. The teeth consist of two long curved tusks, one in each intermaxillary bone, and of large and compound molars in each jaw. The permanent tusks, which are monstrous incisor teeth, are preceded by two small deciduous ones, which make their appearance between the fifth and seventh months, rarely exceed two inches in length and one third of an inch in diameter, and are shed before the second year, their roots being considerably absorbed ; about two months after the milk teeth are shed, the permanent tusks, which are situated to the inner side of and behind the former, pierce the gum when about an inch long, and grow from the base during the whole life of the animal. The molar teeth are remarkable for their size and the complexity of their structure ; there is not more than one wholly, or two par- tially, in use on each side in each jaw at one time ; they are constantly in progress of de- struction and formation, succeeding each other horizontally, instead of vertically as in other mammals ; according to Owen, the molars are successively brought forward until each jaw has had on each side 6, or 24 in all. Each tooth is composed of a number of transverse vertical plates of dentine or ivory, enveloped in enamel, and united together by the cement of crusta petrosa; only a small portion of the crown appears above the gum. This gradual progress of the teeth from behind forward ex- plains how the elephant has always a grinding surface ready to bear the great pressure to which his teeth are always subjected; the constant wear of the grinding surface keeps it in order for mastication ; the manner in which the enamel is arranged on this surface, after the ivory is worn down, enables the anatomist to refer a tooth either to the Asiatic or African elephant. From the oblique position of the molars in the jaws, the anterior portion pierces the gum first, and may be quite worn while the middle and posterior portions are slightly or not at all used, so that these teeth diminish in length at the same time that their depth is worn away ; as the anterior grinding surface becomes useless, the root is removed by ab- sorption, enabling the tooth to be pushed for- ward by that behind. The tusks are formed of ivory and enamel, the former making the central and by far the largest portion ; the tusks exist in both sexes, but are smaller in the females than in the males ; they sometimes measure 9 ft. in length, and weigh over 200 Ibs. the pair ; this great weight is kept in place only by the tight embrace of the socket and surrounding parts, explaining the abnormal direction of the tusks produced either by sud- den and violent or by gentle and long contin- ued pressure. The lower jaw is massive, and prolonged in front, where the extensible lower lip is elongated into a triangular deeply con- cave organ for receiving the extremity of the trunk. The spine consists of 7 cervical verte- brae, 20 dorsal, 3 lumbar, 5 sacral, and from 24 to 26 caudals; the number of ribs is 19, and in some specimens 20, of which 5 or 6 are true. The thoracic cavity is very large, the ribs be- ing continued back nearly to the pelvis, of great size and width; the sternum is long, compressed laterally, and somewhat prolonged in front. The limbs being designed more for strength and solidity than speed, their bones are thick and large ; the shoulder blade is wide, its posterior margin much the shortest ; and the spine, beside the acromial process, has a broad, sickle-shaped prominence extend- ing downward and backward ; there is no clavicle, as the approximation of the limbs to- ward the centre of gravity is necessary to sup- port the weight of the body. The humerus is short and massive, the upper extremity hav- ing a fiat articular surface with large protuber-