which are prominent in the patterns of certain semi-aquatic mammals; and 

 they also correspond closely to the water-shine flecks of aquatic and swamp- 

 haunting birds. (See Chapter XI, p. 61.) Two beasts of this type are the 

 African Water Chevrotain (Hyomoschus aquaticus) and the South American 

 Lape or Paca (Ccelogenys paca). Though belonging to different orders (the 

 Chevrotain being a ruminant and the Lape a rodent) these two animals are 

 much alike in general habits, while in pattern they are almost identical. 

 The ground color of the Chevrotain's coat is richer and redder brown than 

 that of the Paca's, but it bears almost exactly the same system of white flecks 

 — irregular white spots, in places almost or quite confluent, and forming 

 longitudinal chains or stripes. If these two beasts lived in the same swamps, 

 naturalists would very likely consider their superficial likeness a case of • mim- 

 icry.' But since they live on different continents, there is no disputing the 

 statement that they are independently equipped with water-shine patterns of 

 the same simple, generalized type, which occurs the world over both on mam- 

 mals and on birds. 



As the zebras' bands are vertically 'secant,' so lengthwise stripes, of which 

 we see the first signs on the Harnessed Antelopes and the two water-beasts 

 just described, are longitudinally secant, like those of certain gallinaceous 

 birds and sparrows, etc. (Chapter XIII, p. 78). On mammals, this truly 

 striped pattern appears in many forms and many degrees of elaboration, be- 

 ing sometimes merely secant, with no very particular suggestion of back- 

 ground-picturing, and sometimes highly 'pictorial.' Many of the North 

 American Ground Squirrels, and Spermophiles (Tamias and S pernio philus), 

 are marked with bright, longitudinally striate patterns of black and brown 

 alone. The Common Chipmunk (Tamias striatus), of eastern North Amer- 

 ica, has few but highly developed markings, its one composite side-stripe 

 being formed by a central whitish stripe inclosed within two black ones. 

 (See Fig. 93.) Painted thus boldly on the little beast's obliteratively shaded, 

 beautifully dim and flat-looking, honey-brown body, these markings much 

 enhance its elusiveness by distracting the beholder's eye from any faint mod- 



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