8 Herr Max Weber 07i the Origin of Hair 



Yet even were tlie Manldfe also burrowers in the sense that 

 the Dasjpodidse are, it would certainly be surprising that 

 among the large number of most pronounced burrowers 

 among Marsupials, Insectivores, and Eodentsnot a single one 

 should have acquired a coat of scales. Further on we read 

 (p. 547) : — " As their embryology shows, both originate from 

 true, typical, hair-bearing animals, which in consequence of 

 a newly adopted mode of life have acquired a new body- 

 covering." Much is here demanded of embryology. Yet we 

 find in Eomer's paper no new facts as to the development of 

 the integument in Mauis, but merely the statement (p. 545) : 

 " The origin of the scales, which are strikingly large in tlie 

 case of the small Manidse, may well be explained by tlie fusion 

 of several small scales. . . ." This mode of explanation is a 

 personal one on the part of Eomer. I have exerted myself 

 to discover the development of the scales on his behalf, from 

 their earliest appearance onwards, but have observed no trace 

 whatever of a fusion of the scales. Since the investigation 

 is a very easy one, I have no reason to deviate from what I 

 saw and to adopt an explanation which is not based upon 

 observation. 



But also the manner of the occurrence of the scales in 

 Mammals tells against the view that they are to be regarded 

 as a new acquisition of a secondary character in connexion 

 with the mode of life. A few examples may make this 

 clear. 



MyrmecopTiaga tamandua, whose climbing tail is but thinly 

 clothed with hair, has the scales but little more strongly 

 developed than the exclusively terrestrial M. juhata, whose 

 tail is thickly clothed with bushy hair, and in spite of that 

 bears scales. Myrmecoj^haga {Cydothurus) didactyla, with an 

 exclusively arboreal mode of Fife and a typical prehensile tail, 

 has no trace of scales. Of Ptilocercus and Txipaja^ which are 

 the only arboreal Insectivores, Ptilocercvs has, as shown by 

 de Meijere, well-developed polygonal caudal scales, while 

 Tvpaja, with a precisely similar mode of life, has nothing of 

 the kind. Tarsius spect7-um of authors comprises, as I was 

 able to prove *, two species precisely similar in their mode of 

 life. Of these the one, Jhrsius Juscomanus^ Fisch., has 

 distinct scales on a hairy tail, while the almost bare tail of 

 the other, T. spectrum, Pall., is entirely without them. Scales 

 were found by de Meijere upon the thickly haired tails of 

 Petrogale peniciUata and Macropus ruficollis^vfhiXt in the case 



* Max Weber, ' Zoolog. Ergrebnisse einer Raise in Niederl. Ost-Indien,' 

 Leiden, 1893, Bd. iii. p. 2(50. ' 



