2 3 6 



LEMURS. 



FOSSIL LEMURS. 



We have already incidentally referred to the occurrence of several fossil 

 lemurs in the lower Tertiary strata of Europe ; but it remains to be mentioned that 

 other species have been found in the corresponding rocks of North America. This 

 is a very curious and highly important circumstance, since it suggests that while the 

 New World monkeys and marmosets, which have very lemur-like molar teeth, may 

 have taken their origin directly from the extinct lemurs of that hemisphere, the Old 

 World monkeys may have had an independent origin from the ancient lemurs of 

 Europe. 



Curiously enough, although the remains of lemurs have been known for very 

 many years from the lower Tertiary rocks, both of Hampshire and France, it is 

 only quite recently that they have been recognised as such, having been long 

 regarded as belonging to small hoofed mammals. One of these groups of lemurs, 

 represented by several species of different, though relatively small, dimensions, 

 occurring both in England and France, has been described under the name of 

 Microchoeriis ; the term meaning " small pig," and having been applied from the 

 supposed affinity of the creature to the hoofed mammals. These animals were 

 undoubtedly lemurs nearly allied to living forms, their skulls being very like those 

 of the galagos, although their upper premolar teeth more nearly resembled those 

 of the mouse-lemurs. Like all other fossil lemurs, they are, however, distinguished 

 from living forms by the circumstance that the place and form of the lower tusk 

 is not taken by the first of the lower premolar teeth (see p. 203). This is a very 

 important circumstance, since it shows that these ancient lemurs were what zoologists 

 call less specialised than their living relations, and also removes any difficulty as 

 to the descent of monkeys (in which the lower tusk always remains) from lemurs. 



Another and larger European Tertiary lemur, known as the Adapis, carries 

 the series one step still further back, since it has four premolar teeth on either side 

 of each jaw ; whereas, as we have seen, no living lemur has more than three of 

 Here, then, so far as it goes, we have decisive evidence of the 

 approximation of the extinct lemurs to the inferior 

 orders of Mammals, among which four premolar teeth 

 are frequently present ; and we may thus hope in time 

 to discover further evidence of intermediate forms. 



Some of the extinct North American lemurs, 

 with four premolars, do indeed exhibit certain tran- 

 sitional characters ; but it would be beyond the 

 province of the present work to enter upon their 

 discussion. 



We have already called attention at some length to the importance of these 

 extinct European lemurs as helping to explain the peculiar distribution of their 

 modern relatives ; and we may take leave of the subject by mentioning that their 

 occurrence in France and England during the early part of the Tertiary period 

 indicates the prevalence in these countries of a tropical or subtropical climate. 



these teeth. 



THE LEFT UPPER CHEEK-TEETH OF AN 

 EXTINCT EUROPEAN LEMUROID 



(Adapis). 



