1901.] NATURAL SCIENCES OF rillLADELPHIA. 123 



can never liave been of adaptive character, but we are at least 

 entitled to consider that if monkeys in general have flourished 

 luxuriantly with transverse ridges on the crowns of their upper 

 molars, and at most three sacral vertebrae, a slight oblique ridge 

 on the upper teeth and two or three additional vertebrse in the 

 sacrum can hardly be supposed to have had selective value to 

 anthropoids. 



The remaining theory, that of Cope, would account for the con- 

 ditions noted by the process of direct and simple inheritance, and 

 requires no greater amount of assumption than has more than 

 once been justified iu the course of phylogenic speculation. Frag- 

 mentary as are the remains of the Eocene lemuroids which have 

 come to light, they are enough to show that while the group as a 

 whole was generalized, it yet presented at that early period, a con- 

 siderable amount of variety in details, many of which have been 

 preserved in existing lemurs. Of these early forms we have 

 remains of little but jaws and teeth, but the many and curious 

 correspondences which have been noted betw^een anthropomorpha 

 and the Nijctlcehldce are best intelligible upon the supposition that 

 they originated in a group which, possessing the tooth characters 

 shown by each, had associated with them the other structures as 

 well; such may have existed among the Anaptomorphidce, but in 

 the present state of ignorance as regaixls the details of the remain- 

 ing skeletal structure of that group, it would be rash to attempt a 

 close specification, either of the particular form or of its geo- 

 graphical region. 



Cope's view- of the independent origin of the anthropomorpha 

 was based upon the supposed tendency in the human race to revert 

 to a tritubercular form of molar. There are minds to Avhich rever- 

 sion is but a convenient term denoting a process which it is rarely 

 possible to either prove or disprove; but whether or not it be 

 accepted in this case, ^' Prof. Osborn has figured the upper jaw of 

 a Primate^* (possibly Indrodon) from the Puerco beds, possessing 

 quadritubercular upper molars, with traces of an oblique ridge — an 

 observation which greatly fortifies Cope's position. His case of 

 reversion, if admitted, would then lead a stage further back to 



"It is to be observed that Topinard's refutation (L c, p. 707) of Cope's 

 hypothesis is ba*ed upon a misunderstandiug of its real terms. 

 ^^Bull. Am. Mus. of Xat. Hist., 1895, p. 19, fig. 4. 



