MEMOIRS 



OF 



The American Museum oe Natural History 



New Sekies, Volume III 



PART II.— ON THE 8TilU("rURE AND RELATIONS OF NOTHAliCTUS, AN AMERICAN 



EOCENE PRIMATE 



Studies on the Evolutk^n of the Phimates, Part III ' 



By W. K. Gregory 



Platios XXIII-LIX 

 ( INTENTS 



Page 



Preface 51 



Introduction 53 



Previous Discoveries ancl Investigations .55 



The Limbs of Nolhardus; a Comparative Study 62 



Pectoral Limb O'i 



Pelvic Limb 83 



The Vertebral Column of Notharclti.s . 107 



The Dentition and Mandible of Not hard u.s and its Allies; Comparison witii the Adapinse 123 



Adult Dentition 123 



Mandible 144 



Summary' of Occlusal Relations of the Upper and Lower Teeth 149 



Deciduous Dentition 150 



The Skull and Brain Cast of Xuthardiis; Comparison with Adapi.'i 154 



Skull 154 



15rain Cast 107 



The ( 'ochica Auris and ( )ssicula of Xollidrcl n.^: ( 'oinp;i rison with ()( her Primates 10!) 



Cochlea 10!) 



Ossicula 170 



A Review of the Course of the Internal Carotid Artery aTid its Branches in the Basicranial Region of Primates . 171 



The Systematic Position of Notharclu.^ 183 



Summary of the Divergent Evolution of Adapiuie and Notharctime .185 



Sy.stematic Relations of the Notharctinte with the Adapina\ and a Discussion (jf the Value of the " Family" 



in Classification. A Reply to Dr. Stehlin's Criticisms ISS 



Relations of Notharctina^ and Adapina^ with Lemurida', and a Discussion of tiie Probable Origin of the Lcnnn-ida" 1!)7 



Comparison of Nofhardus with the Indrisidiis 214 



Comparison of Nofhardus with the Platyrrhini 217 



Summary of the Structural and Genetic Relations of Nothiirdiis with Other Primates 221 



Taxonomic Conclusions 227 



Inferred Characters of the Common Lcmuriform Stock Ancestral to Adapinre and Notharctinse . . . 22!) 



Summary of the Evolution of the Limbs of Primates 233 



References Cited in the Text 242 



' For Parts I and II, see Bull. Anu-r. Mas. Nat. Ili.st., XXXV, pp. 2;59-:5')5. 



49 



