FLOUNDERS OF GENUS PARALICHTHYS AND RELATED GENERA 



269 



COMMON NAMES 



Since these flounders ;ire common or abunilant 

 fooil fi^shes, it is esjjecialiy desirable for each 

 species to have a distinctive common name which 

 may be uniformly applied to the same species 

 throughout its ranire. An attempt is here made 

 to introduce such conmion names for the species of 

 Paralichthys that occur in the waters of the United 

 States. It is well known to those who deal with 

 the fishes of the country as a whole that the mul- 

 titude of common names applied to a given species 

 is confusing, especially with food fishes that enter 

 the cliannels of trade. Xot only are species often 

 known by different names in different sections of 

 the country, but frecjuently this occurs in adjacent 

 communities of the same State. It is even more 

 confusing when a name is applied in one locality 

 to a particular species, and in another to an en- 

 tirely different species. In this paper, therefore, a 

 distinctive English name is suggested as a uniform 

 counuon name for the species. 



SAMPLING 



The chief cliaracters used for separating the 

 species are of a meristic nature and vary within 

 rather wide limits. The variations are of the usual 

 frequency-distribution type and lend themselves 

 readily to the ordinary methods of statistical 

 studies of such variations. It is evident, there- 

 fore, that in any study of these characters it is 

 important to sample the individuals examined in 

 such a manner that the resulting frequency dis- 

 tribution, as tabulated, represents as nearly as pos- 

 sible the living population of the species in the 

 water. 



The importance of a representative sample in 

 studies of fin ray counts for instance, is forcibly 

 impressed after gaining considerable experience in 

 such studies. It may be readily observed in species 

 in which the number of fin rays varies within 

 considerable limits that sj^ecimens obtained in 

 the same haul of the net will sometimes tend to 

 grou]) themselves either near the beginning or 

 near the end of the frequency distribution of the 

 species as a whole. Therefore, in oi-der to portray 

 adequately the meristic characters for each species, 

 the method of selecting the sample to be studied 

 is of importance. If, let us say. the fin rays of 

 one hundred specimens are enumerated and tab- 

 ulated, and all the specimens are obtained in a 



single iiaul of the net, the lesult is apt not to pre- 

 sent a true picture of the species. On the other 

 hand, if the hundred specimens are taken at ran- 

 dom, one each, from as many hauls in different 

 localities, the result is apt to present a fairly good 

 view of the normal variation of that ciiaiacter 

 witliin the species as a whole. The individuals 

 employed in this study represent specimens ob- 

 tained by methods intermediate between these two 

 extremes. They were those obtained in the ordi- 

 nary course of extensive collecting, when the tend- 

 ency on the part of the collectoi- is to save a few 

 specimens out of each haul as a sample, especially 

 when any haul yields too many individuals of one 

 species. All the individuals tabulated herewith 

 are a composite of many such samples generally 

 ranging from 1 to 10 specimens m each sample. 

 Only three samjiles had more tlian 10 specimens, 

 the highest number being 21. Tlie frequency dis- 

 tributions thus obtained for the more common 

 species probably represent fairly those of the re- 

 spective species, at lea.st near enough for practical 

 purposes. (The question is further discus-sed on 

 p. 276 in relation to tlie tliree common east -coast 

 species.) 



STRUCTURAL DIFFERENCES DISTIN- 

 GUISHING THE SPECIES 



For the practical purpose of the proper distinc- 

 tion of the three common eastern species, it is onlv 

 necessary to enumerate correctly for any given 

 specimen, the gill rakers, the anal rays, the dorsal 

 rays, and the scales. The importance of the 

 character's is in the order stated. These struc- 

 tural characters in combination with evident dif- 

 ferences in the color pattern will serve to distin- 

 guish individual fish of the three common si)ecies 

 of the east coast. Proportional measurements in 

 the east coast species are generally' of secondary 

 importance. However, when all the species are 

 taken into consideration these generalizations do 

 not hold altogether, and the important differenti- 

 ating characters are pointed out under each spe- 

 cies. Also, when all the species of the genus are 

 considered, the structure of the scales, whether 

 cycloid or ctenoid, and the presence or absence 

 of accessory scales is of much importance in classi- 

 fication. 



In distinguishing the species in general, leliance 

 nuist lie ])laced to a lai'ge extent on the nunil)ei- of 



