January 1, 1895.] 



KNOWLEDGE. 



darker hue than the general ground-colour of the fur, and 

 bordered by a narrow black line ; the black line in the two 

 former species being, however, confined to the hinder half 

 of the cloudings. 



3. Mioninah iiitli dark tntnsrersc stri/ics, — Tiger, young 

 lions, wild cat, striped hyrena, aard-wolf {Pmtch's), banded 

 civet (Hi'iiiiiiale), banded mangcose (C'cos.snrc/n/s), zebra- 

 antelope, gnus, zebras, thylacine (Fig. 1), and the water- 

 opossum (Chirontrti's). Among these, it may be noted 

 that in the zebras the stripes on the hind-quarters have a 

 more or less marked longitudinal direction; and whereas in 

 the true zebra and Grevy's zebra they consist of simple 

 dark bands on a light ground, inBurchell's zebra the light 

 areas between the dark stripes are traversed by an inter- 

 mediate stripe of somewhat darker hue than the ground- 

 colour. 



4. Mammals iritit irhite ipots arranged in lorujitiuUnal 

 lines. — Fallow deer and Indian spotted deer ; young tapirs ; 

 the paca (Cai<iijcnt/s) among the rodents ; and the dasyures 

 among the marsupials. Both in young tapirs and the 

 paca the spots tend to coalesce into more or less complete 

 longitudinal stripes, 



5. 2[a})n)ial'< irit/i iihitf transrerse hands.- — The kudu, 

 eland, bongo (I'ra^/fla/i/ius anijasi), and harnessed antelope 

 {T. scriptus), among the antelopes, and Gunn's bandicoot 

 [Peramcles i/imni) and the banded auteater {Mi/niwcnhiKs') 

 among the marsupials. In the harnessed antelope spots 

 occur as well as stripes. 



Many other species might be incorporated in these lists, 

 but the foregoing instances are sufficient to show that no 

 one type of coloration is confined to any particular group, 

 although it may be much more common in one assemblage 

 of animals than in another. 



Several attempts have been made to reduce the coloration 

 of animals to some general law, and among these one of 

 the most notable was published some years ago by Prof. 

 Eimer, of Tubingen, who based his conclusions on a com- 

 prehensive study of vertebrates in general. As the result 

 of his investigations, this observer declared that the following 

 laws might be laid down in regard to colour-markings of 

 animals in general. Firstly, the primitive type of coloration 

 took the form of longitudinal stripes. Secondly, these stripes 

 broke up into spots, retaining in many cases a more or 

 less distinct longitudinal arrangement. Thirdly, the spots 

 again coalesced, but this time into transverse stripes. And 

 fourthly, all markings disappeared, so as to produce a 

 uniform coloration of the whole coat. As a further develop- 

 ment of this theory, it was added that the more specialized 

 features were assumed in many cases more completely 

 by the male than the female, while the primitive coloration 

 often persists in the young. And it was stated that the 

 primitive longitudinal stripes frequently persist on the 

 middle of the back, and likewise on the crown and sides of 

 the face ; examples of the latter survival being shown by 

 the head and face-stripes of many spotted cats, and the 

 dark and light streaks on the sides of the face of the 

 badger. 



Whether these laws hold good for other groups of 

 vertebrates, it is not within the scope of the present article 

 to inquire, and attention will accordingly be concentrated 

 on mammals. If they be true, we should, prim'! facie, 

 expect to find a large number of longitudinally-striped 

 forms among the lower members of the class ; while those 

 of intermediate grades of evolution would be spotted, and 

 the higher types either transversely striped or uniformly 

 coloured. This, however, could only be the case, as a 

 whole, if all mammals formed one regularly ascending 

 series ; whereas, as a matter of fact, they form a number 

 of divergent branches, each containing specialized and 



generalized forms. The inquiry is thus rendered one of 

 extreme complexity ; although there ought, if the theory 

 were true in its entirety, to be a considerable number of 

 longitudinally-striped species among the lowest groups of 

 all. Unfortunately, paleontology, from the nature of the 

 case, can afford us no aid, which fact very materially adds 

 to the difficulty. It may be added that in Prof. Eimer's 

 scheme no distinction is drawn between light and dark 

 markings — that is to say, between the total disappearance 

 of pigment and an ultra-development of the same — and it 

 is obvious that this may be of such prime importance that 

 these two types of coloration have nothing whatever to do 

 with one another. Nevertheless, we may provisionally 

 consider light and dark stripes, and light and dark spots, 

 as respectively equivalent to one another. 



With regard to uniformly coloured animals, there can 

 be no question as to the truth of the theory, since the 

 young of so many animals, such as lions, pumas, deer, 

 pigs, and tapirs show more or less marked striped or 

 spotted markings which disappear more or less completely 

 in the adult. The occurrence of bands on the legs and 

 sometimes on the shoulders of mules and dun-coloured 

 horses, and likewise the presence of dark bars on the limbs 

 of otherwise uniformly-coloured species of cats, like the 

 (.'aifre cat and the bay cat, are further proofs of the same 

 law. Moreover, the fact that in the young of pigs — and 

 to a certain extent those of tapirs — the markings take the 

 form of longitudinal stripes, whereas in the more specialized 

 deer, whether young or old, they are in the shape of spots 

 arranged in more or less well-defined lines, is, as far as it 

 goes, a confirmation of the theory that spots are newer than 

 stripes. And the presence of transverse stripes in the still 

 more highly specialized antelopes tends to support the 

 derivation of this type of marking from spots, especially 

 if it be remembered that the harnessed antelopes are 

 partly spotted. Still, it must be borne in mind that these 

 instances apply only to light markings, which, as already 

 stated, may have a totally different origin from dark ones. 



There are, however, apparently insuperable difficulties 

 as regards longitudinal and transverse striping m mammals. 

 In the first place, instead of finding a number of the 

 polyprotodont, or more primitive marsupials, showing 

 longitudinal stripes, we have in this group only the three- 

 striped and single-striped opossums thus marked, and in 

 these the stripes are respectively reduced to the numbers 

 indicated by their names. This, however, is not all, for 

 the banded anteater — the most primitive of all living 

 mammals (with the exception of the egg- laying mammals) 

 — takes its name from the narrow transverse white stripes 

 with which the back is marked ; while the thylacine 

 (Fig. 1), which cannot in any sense be regarded as a 

 specialized type, is similarly marked with broader dark 

 stripes ; neither of these animals having any trace of a 

 longitudinal stripe down the back. The water-opossum, 

 again, may be regarded as a transversely-striped marsupial, 

 although here the stripes are few in number, and approxi- 

 mate in form to blotches. Although in the same order the 

 dasyures are spotted with white, we have no black-spotted 

 marsupial ; and if such a type formed the transition 

 between longitudinal and transverse stripes, surely some 

 species showing such a type of coloration ought to have 

 persisted. 



Then, again, in the ungulates we have the zebra- 

 antelope, the gnus, and the zebras showing most 

 strongly-marked transverse dark stripes ; but we have no 

 dark-spotted forms in the whole order except the giraffes, 

 while the only ones with dark longitudinal stripes are 

 young pigs. And it would thus appear that, although all 

 the animals above mentioned'are highly specialized species, 



