It has been considered necessary to pre serve the cranium of the Giraffe at present in our possession entire ; consequently, we are unable to offer any account of these sinuses from personal examination, which is the less to be regretted, as Prof. Owen has placed on record the following description of this structure*: " The part of the skull to which the elastic ligament is attached is raised considerably above the roof of the cranial cavity by the extension backwards of large sinuses, or air-cells, as far as the occiput. The sinuses commence above the middle of the nasal cavity, and increase in depth and width to beneath the base of the horns, where their vertical extent equals that of the cere bral cavity itself. The exterior table of the skull, thus widely separated from the vitreous table, is supported by stout bony partitions, extended chiefly in the transverse direction, and with an oblique and wavy course. Two of the most remarkable of these bony walls are placed at the front and back part of the base of the horns, intercepting a large sinus immediately over the middle of the cranial cavity, and from a third and larger one be hind. The sphenoidal sinuses are of a large size." Slight differences in the development of the cranium are found in Giraffes inhabiting respectively the niore northern or southern regions of Africa, these peculiarities having especial relation to the position and approxi mation of the horns. In the Abyssinian specimen (about two years old) dissected by us, several particulars were noted, a few of which are here selected + In this list will be remarked the extreme elongation of the bones of the face, as shown by the distance of the incisive angle from the central prominence—the great depth of the orbits—the narrow space between the bases of the horns the length of the jaw—and more particularly the extended vertical dia meter of the condyloid facets of the occipital bone. The elongation of these articular sur faces in the direction indicated, permits of the head being drawn into a line with the neck, and Prof. Owen states, from observing this action in the living animal, that he has seen it stretched backward beyond this line.
Horns. — In the Giraffe we have a unique example of solid persistent horns, completely invested with a hairy integument. They are placed on two bony elevations, having a position analogous, in some respects, to that of the osseous cores of the Stags ; but, being separated from them by a synchondrosis, they are to be regarded as independent develop ments or " epiph3ses " and not " apophy mai " outgrowths (fig. 328.). As has been al ready observed, the protuberances are formed in part by the parietal and frontal bones, the coronal suture passing transversely across the centre of each osseous expansion, from side to side. The bones are easily detached by maceration (at least in the younger ani mal), and when withdrawn, there is brought into view an intervening sheath-like perios teum, which can also be separated from the concavity at the base of the horn. This cup shaped hollow, owing to the columnar dis position of the osseous larninm, and the very numerous perforations for the passage of nutrient vessels, presents the appearance of a sieve, depressed into a conical form. Both in the Cape and Nubian varieties a sexual difference obtains in reference to the extent to which the horns are developed. In the male adults they are larger and more closely approximated at the base than in the females, and, according to Prof. Owen's observations on the horns of the Cape Giraffe, " their expanded bases meet in the middle line of the skull, so that they would entirely conceal the coronal suture even if it were not early obliterated in this sex." • The basal portions of the horns in the females are widely sepa rated. In our specimen (a Nubian male) the internal and lower margins of the horns remain, severally, half an inch apart, and the interfrontat suture is still distinct throughout its entire leng,th. In regard to the asserted existence of a third horn surmounting the anterior central protuberance, an examination of the cranium, above alluded to, only serves to confirm the extended observations and conclusions of Prof. Owen on this subject.
AVe have shown that this elevation is due to an enlargement of the subjacent frontal si nuses, and in this respect it resembles the posterior horn-shaped apophyses. It must be remarked, however, that although, in our example, there is no superimposed osseous deposit, there is, nevertheless, a cartilaginoid thickening of the periosteum in that situa tion; this, we can readily believe, might con stitute a nucleus favourable to, the formation of an epiph)sis similar in all respects to the true horns lately described_ We have not had an opportunity of inspecting the crania in the museum of the Royal College of Sur geons, London, but, through the kindness of Dr. Ball, have examined the skeleton of a male Giraffe which died (during sexual ex citement) at the Dublin Zoological Society's Gardens, and which is now preserved in Dr. Harrison's Anatomical _Museum. In this in dividual the central cranial eminence is not smooth as in our specimen ; on the contrary, it is particularly rough, owing to the deposi tion of osseous nodules, which bear a marked resemblance to the irregular bony laminm prolonged from the attenuated margins of the bases of the true horns. If these rough prominences could be shown to be separable by maceration, we might with good reason infer the rudimentary existence of a third horn ; if, on the other hand, they are merely exostoses or outgrowths (and to this opinion we incline), we think their deceptive aspect offers, in sotne measure, an explanation of the incorrect description of this structure recorded by Cuvier, and the inaccurate figure given by Riippell.* The deciduous branching horns of the deer present two well-marked morphological types, — one group possessing rounded antlers, and the other having them more or less flattened and palmated. Of the former, characteristic examples are seen in the horns of the Roe buck (C. capreolus) and Red Deer (C. ela phus), — and of the latter, in the Elk (C. alces) and Fallow Deer (C. damas). The re markable periodical development of these cra nial outgrowths is most interesting in a ph) sio logical point of view, and both types of struc ture exhibit the same general law of increase. The male calf of the Red Deer at the sixth month differs from the female of the same age, in having two small elevations or " bos sets," which represent the first indication of horns. These processes acquire, in the second year, the form of simple unbranched stems or " dags " (a, fig. 339.), at which date the deer is designated a " brocket" by the English, and by the French a " daguet." The da.,mr like horn being shed, its place is occupied in the third year by another, carrying usually one, but sometimes two, and even three branches or " tynes " (b, c); in this condition he is called a " spa3ard." The horn of the fourth year assumes a more complex aspect (d, e), and the summit or " crown " of the stem begins to spread and divide ; at this stage he is styled a " staggard." At the fifth year there are five OF six branches, and at this period he is termed a " stag." At and after the sixth and seventh years the number of "tynes" is very variable, and the growth of the horn being now perfected, the individual is technically denominated a "hart" (f). The palmated horns of the Fallow Deer exhibit similar gradations of development. At the second year the " buck-fawn" or "pricket " puts forth a simple " dag " or cylindrical shaft (a, fig. 340.), which is slightly bent forward. In the third year the branch ing commences, and he is said to be a "sorel" (b). The antlers in the fourth year grow. more numerous, and the stem is bifid at the summit (c); at this period the Fallow Deer is entitled a " sore" by sportsmen. After this date the upper part of the brain or shaft becomes more palmated, and irregular serra tions or " snags " are produced at the margin (d); the animal is now a " buck of the first head," and, as age advances, the snags en large, and take on, more or less, the appear ance of true antlers. In the Rein Deer the horns undergo a similar metamorphosis ; they are of great size in both sexes, but are some what less branched and slender in the fe male ; the brow-antlers are much prolonged forward over the forehead.