18 TRICIIOLOGIA MAMMALIUM ; 



horned species,) grow from the tegument covering the nose, to which they adhere without 

 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. 10 a, 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.) 



THE HORN OF THE RHINOCEROS, IN THE ACADEMY OF NATURAL SCIENCES OF PHILADEL- 

 PHIA. Examination and description of the horn of a two-horned Rhinoceros in the Academy 

 of Natural Sciences of Philadelphia. Length, from the base to the point, 15 inches and 

 T V Of this 1 inch and T \ appears to have been buried in the skin. Circumference at the 

 base, 14 inches -fa. Diameters, 4 T \ by 4 ^ . The inferior termination calyx shaped ; 

 depth of calyx, 2 inches. Circumference, at the former junction with the epidermis, 12 

 inches ; apex oval ; diameter, T ^ by ^ 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 slight longitudinal fissures. 



Examination of the Hair of the Ear of the Rhinoceros. Length, T % of an inch ; shape, 

 cylindrical ; diameter, 2-| T , gradually tapering to j^Yo 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 ^ ^ of an inch. Shaft undulating ; 

 apex rounded, sometimes furcated. 



OF 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 



