54 ANNALS NEW YORE ACADEMY OF SCIENCES 



Use of Characters 



The problem of defining the characters or the kind of characters 

 which distinguish species, genera, etc., has never been satisfactorily 

 solved. The writer will venture to consider only that part of it which 

 concerns the distribution of South American fishes. 



In the main, there are two schools of ichthyologists, the American 

 and the English. The American school makes many divisions of the 

 families, genera and in some cases the species. The English school has, 

 as a rule, been more conservative with taxonomic divisions and has 

 therefore fewer but larger groups. In support of the American school 

 may be given the results of the excellent experimental evidence obtained 

 by de Vries, Tower, Johannsen and others, which indicate that the sys- 

 tematic species is a complex one. In other words, this experimental 

 evidence tends to split up the species of the systematist into several ele- 

 mentary species. Much can be said in favor of this finer analysis of 

 species from the experimental standpoint, but little can be said in favor 

 of it from the standpoint of the systematist, because he does not know 

 whether his specimens are hybrids, whether they have a wide range of 

 fluctuating variation, whether they are mutations or whether the pecu- 

 liarities of the observed somatic differences are inherited or not. 



Therefore, from the standpoint of geographical distribution, it ap- 

 pears that the English system, with its fewer divisions and divisions 

 based on more than single characters, is the better one, at least until we 

 have analyzed our species experimentally. 



In reference to what characters are important from the standpoint of 

 the fish geography of South America, we are exceedingly fortunate, at 

 least in the case of Priscacara, a fossil cichlid described by Cope from 

 the Eocene of Green Eiver, Wyoming. 27 



From this interesting genus and from a comparative study of the 

 South American Cichlidse, we are able to state with a high degree of 

 certainty that the ancestral Cichlidge had the following characters: 

 Three anal spines; short gill rakers; more than one row of short conical 

 teeth in each jaw; pharyngeal teeth; ctenoid scales; serrated preoper- 

 culum; a continuous spiny and rayed dorsal with more than eight 

 spines ; single naris or a tendency for narial coalescence ; a rather short, 

 deep body, and a tendency to form a two-parted lateral line. 28 



27 I have examined some of Cope's types and believe that Woodward and Pellegrin are 

 correct in considering Priscacara a fossil cichlid. 



28 It must be granted that it is difficult, if not impossible, to decide in the case of all 

 of the characters of fossil and living forms which characters are paleotelic and which 

 are cenotelic, but we can agree on at least a sufficient number to show that no living 

 cichlid fish could have given rise to those of both Africa and South America. 



