120 PROCEEDINGS OF THE ACADEMY OF [March, 



Baird. "- Later* I stated, '^Percopsis guttattis Agassiz has been 

 credited to the Delaware River by writers with reference to its 

 capture by Dr. Charles C. Abbott. However, Dr. Abbott tells me 

 that he has never taken this fish in the Delaware, and also that he 

 has never seen a specimen from any part of the same river system. 

 The confusion he attributes to the remark which he made that 

 Baird had reported it from Easton, Pa." Its occurrence in the 

 Delaware was previously admitted by Jordan and Evermann,^ and 

 copied recently by Kendall,^ in his paper on the identity of Percopsis 

 cjuttatus Agassiz with the earlier Salmo omiscomaycus AValbaum. 

 Uhler and Lugger first record^ it from the lower Potomac and also 

 state, ''Prof. Baird has seen specimens from the Susquehanna 

 River." Subsequently Smith and Bean mention it* from the 

 Potomac basin in Rock Creek and Cabin John Run, where "it is not 

 abundant, so far as known." 



That Prof. Baird's Delaware River record was correct is quite 

 likely, as Messrs. Mattern have recently presented the Academj^ 

 with a number of examples, taken in the Jordan Creek near Allen- 

 town, or about three miles above the mouth where it debouches into 

 the Lehigh River. These little fish were captured August 26, 1916. 

 They were quite active, dwelling in the clear waters of the stream, 

 and associated with shiners, black-nosed dace, suckers and darters. 

 They are free swimmers, and travel in schools composed entirely of 

 their own species, and none were secured in water less than a foot 

 in depth. Their capture is of interest as serving to record with 

 certainty the trout-perch in the Delaware River basin. 



The allied western Columbia differs chiefly in the more robust 

 dorsal and anal spines, the latter two in number. In my examples 

 of the trout-perch the dorsal and anal spines are slender. As the 

 species is somewhat variable, the following variations are from 15 

 examples. Head 2| to 3f ; depth 3f to 4i; D. Ill, rarely IV, 9 or 10, 

 rarely 8; A. I, 7, frequently 6, rarely 9; V. I, 7; scales in lateral line 

 variable, usually 44 to 52, rareh^ 40, to caudal base, and usually 2 

 on latter, often 3; 6 scales above 1. 1., often 7, rarely 5; 8 scales below 

 1. 1. to anal origin, sometimes 7; snout 2f to 3 in head; eye 3 to 3|; 

 maxillary 3 to 3^; interorbital 3| to 4|; length 45 to 77 mm. In 

 the smaller examples dark spots on the back are larger and few. 



4 Rep. N. J. State Mus., 1905 (1906), p. 274. 



5 Bull. U. S. Nat. Mus.. No. 47, I, 1896, p. 784. 

 «Proc. Biol. 8oc. Wash., XXIV, 1911, pp. 45-52. 

 ^ Rep. Com. F. Md., 1876, p. 129. 



8 Bull. U. S. F. Com., XVIII, 1898 (1899), p. 185. 



