152 PROCEEDINGS OF THE ACADEMY OF [Jan., 



members of the same. Thus among the Prosimige, for example, the 

 oldest members of the group, the Hyopsoclinse, possessed 44 teeth = 

 3 ' I ' ^ 3 in each jaw, the more recent Adapidae 40 teeth = | ' i\' ^ , 

 the most recent LemuridjB 36 teeth = |^ ^ | | , the Platyrrhin^e 36 teeth 



with the exception of the Arctopitheca 32 teeth = ^ 132' ^'^^^ filially 

 the Catarrhinse, including the anthropoid apes and man, 32 teeth = 

 g ' ^ ' ^ 3 . It is highly improbable, if not impossible, therefore, to say 

 the least, that Platyrrhine monkeys with 36 teeth should have descended 

 from Catarrhine ones i^rovided with only 32; that 4 premolar teeth, 

 absent in the ancestors, once lost, should reappear again in their de- 

 scendants — an objection that ecjually applies to Cope's derivation of 

 Cehus with 36 teeth from Hapale with 32, as previously mentioned. 



Further, the Platyrrhine monkeys resemble lemurs in many more 

 respects than in the mere number of the teeth, thus showing their 

 inferior position in zoological rank as compared with the Catarrhines. 

 Thus, for example, the oblique ridge extending from the anterior in- 

 ternal cusp (protocone) to the posterior external cusp (metacone) of 

 the upper molars in Ateles and Mycetes, and many other South Ameri- 

 can monkeys, is present in certain lemurs, such as Nycticehus, Ardo- 

 cebus, Loris, as also in anthropoid apes and man, though absent in the 

 remaining Catarrhines.^^ Now the presence of this oblique ridge in 

 the upper molars of lemurs, apes and man was regarded by so high an 

 authority as Cope as such an important feature in their structure that 

 it largely influenced that great paleontologist in suggesting the view, 

 already alluded to, that man and apes are the direct descendants of 

 lemurs rather than of Catarrhines. 



It is obvious, however, that if Cope's argvmient is of any force in the 

 above instance, it must be of even greater cogency in showing that 

 Platyrrhine monkeys have descended from lemurs, since lemurs and 

 Platyrrhina? not only exhibit the "oblique ridge" in their molars, but 

 possess many other structiual features in common, whereas lenuu's are 

 relatively so low in the zoological scale that they are not regarded liy 

 most anatomists as being primates at all. Indeed, Cope might just 

 as well have argued that man has descended from a Platyrrhine monkey 

 as from a lemur, the evidence adduced being about as good for the one 

 view as the other; for even if the "centre of motion" of the vertebral 

 column and the " anticlinal vertebra, " the number of vertebrae entering 

 into the formation of the sacrum, etc., are only the same in man, 

 anthropoids and Nycticebidce,^^ nevertheless in other respects — in fact, 



1^ Tomes, Dental Anatomy, 1876, pp. 7, 370. 



1® Flower, Osteology of Mammalia, 1870, pp. 47, 24, 60. 



