352 Bulletin American Museum of Natural History. [Vol. XXVII, 



The order Taxeopoda seems to be a very artificial assemblage, held 

 together chiefly by a more or less negative character of the carpus and tarsus. 

 To judge from the arrangement of its "suborders," the Chiromyidse are no 

 more nearly related to the Lemuridae than they are to the Hyracoidea. 



The distribution of the families of Primates seems very bad. The 

 Primates are unjustifiably grouped with the Condylarths and Litopterns. 

 The Litopterns are widely separated from their relatives, the Toxodonts. 

 The order Diplarthra is shown below to be an unnatural group (see pp. 385, 

 400). The division of the Artiodactyla is confused and open to criticism in 

 many respects. 



Several classifications of the Ungulates as a whole appeared between that 

 of Cope and that of Weber in 1904. The classification embodying the most 

 novel features was that of x\meghino in 1905, 'Recherches de Morphologic 

 Phylogenetique sur les Molaires superieures des Ongules' (1904, pp. 511- 

 526). Many of Dr. Ameghino's families are founded upon very imperfect 

 material especially teeth not associated with skulls or limbs. One of the 

 negative results of modern studies is that such material in manv instances 

 serves rather to raise new, than to settle old, questions of relationship. Even 

 in groups in which the entire skeleton and soft anatomy is fully known 

 {e. g., Tubulidentata, Pholidota, Hyracoidea, Sirenia) it is sometimes very 

 diflScult to settle positively the precise relationships with other orders; while 

 in many cases surprising similarities in the dentition (e. g., between Notoryctes 

 and Chrysochloris), do not prove ordinal kinship (c/. p. lOS above). For 

 these and similar reasons phylogenetic conclusions and classifications which 

 are based either upon superficial similarity in molar patterns or upon equally 

 adaptive features of the skull and limbs are apt to lack certainty and per- 

 manence. 



The labors of ]Marsh, Cope, Osborn, Scott, Schlosser, Wortman, Deperet, 

 Stehlin and others upon different groups of Ungulates, in so far as they have 

 affected the general classification, are reflected in the following scheme 

 given by Weber (1904). 



1904. Weber. 



Ungulata [term used in a superordinal sense]. 

 Diplarthra. 



I. Ordn. Perissodactyla.' 



Titanotheroidea. Palaeosyopidae, Titanotheriidae. 

 Hippoidea. Equidae, Palaeotheriidae. 

 Tapiroidea. Tapiridae, Lophiodontidae. 

 Rhinocerotoidea. Hyracodontidae, Amynodontidse, 

 Rhinocerotidae. 



1 Classification after Osborn, 1898. 



