RevieiDS — Prof. Copers Extinct Vertebrates of N. America. 469 



and that in our own opinion it is preferable, as fresh discoveries 

 indicate forms connecting groups widely separated at the present 

 day, to unite those existing groups rather than to form fresh ones 

 for the reception of the intermediate forms. Thus, taking the 

 ungulated mammals as an instance, we find that on page 1121 of 

 the memoir on the 'Amblypoda,' there are four so-called orders 

 respectively named the Dlplarthra, the Amblypoda, the Taxeopoda, 

 and the Proboscidea ; all of which we think are best included in the 

 order Ungulata, as it is now very generally employed by English 

 palgeontologists. Even if this view were not accepted, it would 

 surely have been preferable to retain the term Ungulata for the two 

 suborders Perissodactyla and Artiodactyla (the Ungulata Vera of 

 some English writers), rather than to invent for them the entirely 

 new term Diplarthra, in which guise they are scarcely recognizable 

 by the student of recent zoology. Similarly the recent Hyracoidea 

 are relegated to a minor group of the so-called order Taxeopoda, when 

 ■we should have thought it would have been better to retain the former 

 well-known term in the larger sense, and include in it (of course 

 presuming that the affinity be a real one) the allied fossil forms. 



Another instance occurs in the case of Eycenodon and a host of 

 allied extinct forms, which (together with some of the recent 

 Insectivora) Prof. Cope (' The Creodonta,' op. cit.) refers to the sub- 

 order Creodonta of a large heterogeneous order Bunotheria ; — the 

 remaining Insectivora (judging from an earlier work) being re- 

 garded as another suborder of equal value with the Creodonta. 

 Now we confess that we are unable to accept the division of the 

 modern Insectivora as here proposed ; and we think that as Hyceno- 

 don and its allies may be pretty safely regarded as ancestral forms 

 connecting the modern Carnivora and the Insectivora by almost 

 insensible gradations, it would be preferable that they should be 

 affiliated to one or other of these orders, — our inclination tending to 

 the Carnivora. This appears to us as a more advantageous plan than 

 creating a suborder of a new order, which, after all, cannot be rigidly 

 defined. That the result of this affiliation would be the impossi- 

 bility of drawing any definite line of demarcation between the 

 Carnivora and the Insectivora, we are fully prepared to admit ; and 

 if any change were to be made in reference to these orders, we 

 should prefer the inclusion of the latter, as a suborder, in the 

 former. Eegarding, then, the so-called Creodonta as affiliated to the 

 Carnivora, it may be remarked that these early insectivoroid 

 forms lacked the grooved astragalus, and the compound scapho- 

 lunar of the modern Carnivores ; the absence of these specialized 

 characters being precisely what we should expect to find in early 

 generalized forms, which may have been ancestral both to the 

 Carnivora and the Insectivora. 



In regard to his families and genera. Prof. Cope is logically con- 

 sistent to his views of the value of ordinal groups, and consequently 

 makes them more numerous than we ourselves should be disposed 

 to consider advisable. After all, however, these different views of 

 classification are but matters of comparatively minor moment, which 



