SKULL 



SKUNK 



493 



(d) The Degree of Projection of the Jaws. We 

 have seen that the human skull, when compared 

 with the skulls of lower animals, presents a small 

 face extended vertically, and thus placed under the 

 anterior part of the cranial box. Prominent jaws 

 therefore indicate an approach to an animal type, 

 especially when associated with a receding fore- 

 head. The degree of projection is expressed by 



Fig. 6. Lateral View of three typical Skulls : 



a, Australian, prognathous ; b, African, mesognathous ; 



c, European, orthognathous. (After Tylor.) 



the gnathic index of Flower, and is obtained by 

 comparing the basi-alveolar length with the basi- 

 nasal length. When the gnathic index is below 

 98, skulls are said to be orthognathous ; from 98 to 

 103, mesognathous ; above 103, prognathous e.g. : 



Onmtblc Index. 



English 86 



Chinese 99 



Eskimo 101 



FU 1 Islanders 103 



Native Australians (aboriginal) 104 



() The form of the nasal skeleton and its anterior 

 openings is also subject to variation, and so its 

 height and width may be measured, and the rela- 

 tion between the two expressed as a nasal index. 



Nasal index below 48 = leptorhine. 



M from 48 to 53 = mesorhine. 



ii above 63 = platyrhine. 

 For example : 



Mail MSB, 



Eskimo 44 



English 46 



Chinese 60 



Native Australians (aboriginal) 67 



In a similar way the form of the orbit is subject 

 to variation, hut this is of less consequence than 

 the nose. Other measurements of the face skeleton 

 are also made. A time-honoured measurement, 

 long thought to be sufficient in itself for founding 

 a classification of races, was the Facial Angle of 

 the Dutch anatomist Peter Camper (a.v., 1722-89). 

 This was obtained by drawing one line from the 

 centre of the forehead to the most projecting part 

 of the upper jaw just above the incisor teeth, and 

 another from the opening of the ear to the base of 

 the nasal opening ; between these was contained 

 the facial angle. 



For the relation of craniometry to the science of man, 

 ee ETHNOLOGY and works there cited. See also the 

 articles ANTHROPOMETRY, ANTHROPOID AITS, BBAIN, 

 MAMMALS. MAM, I'HHESOLOOY, SKELETON, VERTEBHATA ; 

 Huxley's Croonian Lecture (1868); Huxley's Anal, of 

 Yerteb. Animals (1871); Parker's Morphology of the 

 Stall (1877); and for summary, Balf cur's Embryology 

 (voLii.); Broca, Instrucliont Craniologiquet et Cranio- 

 mttriquei ; Flower, Cat. of Mas. of Roy. Coll. Surg. of 

 Eng. (rrt i. 1873-79); Turner, Challenger Reports, 

 Zoology, x. (1888); Schmidt, Antkropoluyiiche Methoilen 

 ( 1888 ) ; Benedikt, Kraniometrie und Kephalometrie 

 (1888). For the illustrative tables in this article we 

 are indebted to the summary in Quain's Anatomy 

 (lOthed.). 



Skunk (Mephitis), a genus of small carnivorous 

 quadrupeds of the family Mustelidce. The l>ody is 

 elongated, and usually much arched ; the tail long, 

 and thickly covered with long, fine hair ; the head 

 small, with thick, blunt snont ; the legs short, and 

 the paws comparatively large, with five incom- 

 pletely divided toes. The general colour is black 

 and white. The power, characteristic in some 

 degree of all the Mustelidse, of forcibly discharging 

 the fetid secretion of the Anal Glands (q.v.) is in 

 the skunks enormously developed. All the species 

 are American, and, as they differ little in habit, 

 the Common Skunk (M. mephitica) may be taken 

 as typical of the whole genus. The common skunk 

 an animal about the size of a cat has fur of a 

 glossy black ; on the forehead is a patch of white 

 diverging into two lines which extend the whole 

 length of the back and meet again in the beautiful 

 busny tail. The under surface of the tail is also 

 white, and, as it is usually carried erect or laid over 

 against the body, the white is regarded by some 

 naturalists as a 'warning colour.' Thus Mr Belt 

 writes: 'The skunk goes leisurely along, holding 

 up his white tail as a danger-nag for none to 

 come within range of its nauseous artillery.' The 

 common skunk is found throughout North America, 

 but is most abundant in the Hudson Bay region. 

 It chiefly frequents high-lying, bushy, or even rocky 

 districts and the hanks of rivers, remaining concealed 

 in its burrow by day, but emerging at dusk in search 

 of the worms, insects, birds, and small mammals 

 which form its food. Its movements are slow and 

 leisurely. It never attempts to run away if pur- 

 sued, for, feeble and defenceless as it looks, it is 



Common Skunk (Mephitis mephitica). 



most efficiently protected by the possession of a 

 nauseous fluid, the discharge of which neither man 

 nor beast will wittingly provoke. Should an un- 

 wary intruder venture too near, the skunk turns its 

 back, erects its tail, and, by means of a muscular 

 contraction, ejects the contents of its anal pouches 

 with a force which carries them to a distance of 

 from 8 to 10 feet. So penetrating is the evil 

 odour of this fluid that it is perceptible a mile oft", 

 and has l>een known to cause nausea in persons 

 within a house with closed doors from which the 

 animal was a hundred yards distant ; and so per- 

 sistent is it that clothes defiled by it can only lie 

 purified by prolonged hanging in smoke. It is 

 said that the fluid has irritating properties which 

 excite severe inflammation of the eyes, and cases 

 are cited of Indians who have thus lost their eye- 

 sight. The skunk is hunted for its fur, which is in 

 considerable demand ; but the hunter must be 

 careful to avoid alarming the animal, and thus 

 causing it to discharge its obnoxious fluid. Skunks 

 usually raise from six to ten young in a season. If 

 taken young they are easily tamed and make pretty 

 pets, for they are cleanly in habit and rarely 

 emit their offensive secretion save when provoked. 

 The Long-tailed Skunk ( M. macnira ) is found in 

 central and south Mexico, and a much smaller 

 species (M. pvtortus), with four white stripes, 

 ranges from the southern states to Yucatan and 

 Guatemala. 



