PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 243 



NOTE OUT PEBCA FLAVESCENS.* 

 By Dr. FRANZ STEINDACIINER. 



Dr. Franz Steindachner, in the Sitzungsberichte of the Vienna 

 Academy for July, 1878, makes some interesting statements regarding 

 the American Yellow Perch, of which a translation is given below: — 



u Perca flavescens of Mitchill, Cuvier, and others, can be regarded only 

 as a variety of Perca fluviatilis, and the opinion of the ichthyologists 

 prior to Cuvier was the correct one. 



The pronounced striation of the operculum, which is a characteristic 

 of P. flavescens, is not always present in American specimens, and 

 Holbrook has already remarked in his description of Perca flavescens 

 (Ichthyology of South Carolina, p. 3), u with radiating striae more or 

 less distinct." 



During my stay at Lake Winnipiseogee, New Hampshire, I frequently 

 saw specimens with very indistinctly striated, or with perfectly smooth 

 opercles. A much stronger argument for the identity of Perca flavescens 

 with Perca fluviatilis lies in the fact that in the vicinity of Vienna 

 occasional individuals with more or less strongly furrowed opercles are 

 taken, and also in the Neusiedler Sea ; in the Sea of Baikal and its 

 tributaries I obtained several specimens with very strongly striated 

 opercles. During my travels in England I was able to find only the 

 typical European form of Perca fluviatilis with the smooth opercle. 



In my opinion, only two species of Perca can be distinguished, namely, 

 Perca fluviatilis, Linn., with two not very sharply defined varieties, viz, 

 var. europea and var. flavescens or americana, and the high northern form 

 Perca Schrerikii, Kessl. 



In the number of longitudinal and vertical rows of scales, Perca 

 fluviatilis cannot be distinguished from P. flavescens, both varieties 

 having 7 to 10 (generally 7-9) scales between the base of the first dorsal 

 spine and the lateral line, in a vertical row. 



In Western North America there are known no members of Perca or 

 any nearly allied genus, while in South America the rivers of Southern 

 and Middle Chili and of Patagonia are inhabited by several (apparently 

 only two) species of the Perai-like genera Perciclitliys and Percilia? 



* Prepared by G. Brown Goode. 



