18 TRICHOLOGIA MAMMALIUM; 
horned species,) grow from the teeument covering the nose, to which they adhere mithout 
having any connexion with the subjacent bones. 'They have a sub-pyramidal shape, and 
are composed of parallel hairs, agglutinated together into a solid mass by a material which 
acts as a cement. This fibrous structure is most distinctly seen at the base of the horn, 
where the ends of the fibres project from the surface like those of a brush. When these 
horns are divided transversely, as in fig. 10a, and examined with the microscope, a great 
number of orifices are seen, marking the empty spaces that intervene between the hairs; 
and if the section be made in a longitudinal direction, as in fig. 10 b, the same spaces give 
rise to the appearance of parallel grooves. These (so called) horns are not deciduous, like 
those of the stag ; but continue to adhere to the skin, and to grow from the root, in propor- 
tion as they are worn at the extremity. (See Roget An. and Veg. Phys. 356.) 
Tue Horn or THE RHINOCEROS, IN THE ACADEMY oF NaTuRAL Sciences OF PHILADEL- 
puta. Examination and description of the horn of a tivo-horned Rhinoceros in the Academy 
of Natural Sciences of Philadelphia.—Length, from the base to the point, 15 inches and 
z4- Of this 1 inch and ,8; appears to have been buried in the skin. Circumference at the 
base, 14 inches ;°;. Diameters, 4 |8; by 4 545. The inferior termination calyx shaped ; 
depth of calyx, 2 inches. Circumference, at the former junction with the epidermis, 12 
inches ; apex oval; diameter, ;, by 5'5 of an inch. The surface in the interior of the | 
calyx rugous and deeply fissured. The exterior striated longitudinally. The main body 
corneous and solid, except some shieht longitudinal fissures. 
Examination of the Hair of the Ear of the Rhinoceros.—Leneth, 58, of an inch; shape, 
2 AO 
cylindrical ; diameter, 54,, gradually tapering to ;5'-, of an inch. Color, brown. Button 
resembles a mere swelling of the posterior portion of the shaft, slightly curved and pointed. 
When crushed, fibres are exhibited of the diameter of 5.5, of an inch. Shaft undulating ; 
apex rounded, sometimes furcated. 
Or Spines.—The word is from “ Spina,” a thorn or prickle. 
A few animals only have spines; such as the porcupine, the hedgehog and the pecary. 
THe SPINES oF THE PorcuPInE.—The Porcupine (Hystrix Dorsata, see Aud. and 
Back. Quadru., 1 vol., 277.) 
Pile, at the roots yellowish-white, tipped with black. Head, cheeks and sides of the 
neck, grayish; legs, of dark brown. A whitish band two inches broad from the top of the 
shoulder on each side, towards the lower part of the neck. ‘The long hairs on the dorsal 
line are so broadly tipped with black, that the animal, on these parts, appears of a blackish 
color; along the sides, however, the alternate annulations are so conspicuous that it has a 
deep gray or grizzled appearance. On the chest, outer surface of the shoulders and 
thighs, it is of a darker color than on the sides. Immediately behind the lightish collar on 
the shoulders, the hairs are dark, rendering the collar or band more conspicuous. 
‘The young have a uniform shade of red. A spine now before us measures in length 
