36 Mr. E. D. Cope on the 



Prof. Jones alludes to Polythalamia being included ; but I 

 cannot find any case or see any indication of this in ' Die 

 Corallenth. d. R. Meeres ;' but some of the larger Foraminifera, 

 as Polytrema, have been taken for Bryozoa quite recently, as 

 by Risso, Heller, and others. Such mistakes will be made 

 until our faunas have been more fully investigated; and 

 it is a matter of surprise that Ehrenberg included so few 

 extraneous genera among his Bryozoa. 



A friend, writing to remonstrate with me for using the term 

 Bryozoa in a paper I recently wrote, says " group names are 

 indications of advancing scientific knowledge ; and not to vise 

 the best is to keep science back." In this I agree, but think 

 that the comparison of Ehrenberg's exacter definitions and 

 Thompson's imperfect conceptions must leave us fully con- 

 vinced that in Ehrenberg we have the clearest proof of ad- 

 vancing knowledge. 



If Thompson's name stood alone, of course, no one would 

 question it ; but as the two names are in use, we have to 

 decide between them. U'Orbigny, Hagenow, Bronn, Van 

 Beneden, Reichert, Reuss, Nitsche, Kirchenpauer, Smitt, 

 Romer, Claparede, Manzoni, Ehlers, Barrois, Joliet, and 

 many others have all used Ehrenberg's term, against which 

 are a few polyzoists, all, except Sars, in England and Ame- 

 rica, some of whom certainly occupy most leading positions ; 

 but it should not be forgotten that even in England the use 

 of the name Polyzoa is comparatively a recent innovation. 



The points to be considered are : — (1) that the question is 

 not one of dates ; (2) that Thompson did not define any group 

 of animals, and used Polyzoa to indicate only a polypide ; 

 (3) that Ehrenberg definitely separated the Bryozoa, and, con- 

 sidering how little attention they had then received, was very 

 successful in the indications he gave as to which animals 

 belonged to this group. 



La Stazione Zoologica, Naples, 

 Nov. 14, 1879. 



IV. — On the Genera of Felidad and Canidse. 

 By E. A Cope*. 



Felidse. 



The discovery of extinct species from time to time renders it 

 necessary to reexamine the definitions of the families and 

 genera into which living forms naturally fall. We thus learn 



* From the ' Proceedings of the Academy of Natural Sciences of 

 Philadelphia,' May 1879. 



