GREAT LAKES COREGONIDS 



335 



Dr. Leonard Stejneger, of the United States National Museum, for advice pertaining 

 to nomenclature. 



Certain individuals and institutions have contributed through the gift or loan 

 of specimens. I acknowledge with particular pleasure the kindness of Dr. W. A. 

 Clemens and John Dymond, who placed the University of Toronto collections of Lake 

 Nipigon at my disposal, and of Prof. John Lowe, of the Northern Normal College at 

 Marquette, Mich., for the preparation of special collections from Lake Superior. 

 Thanks are also due the authorities of the Field Museum of Natural History, the 

 Wisconsin Geological Survey, and the United States National Museum for the loan 

 of their coregonid collections. 



To the many fishermen of the Great Lakes, through whose hearty cooperation 

 were obtained the materials and data on which this paper is based, I owe the 

 greatest debt. 



SPECIES OF COREGONIDS IN THE GREAT LAKES 

 ANALYSES OF THE SPECIES 



LAKE NIPIGON 



A. Two flaps between the openings of a nostril; exposed area of the scales of the lateral line not 

 conspicuously smaller than that of the adjacent rows; gill rakers more than 23, relatively long 

 and slender; maxillary usually contained less than 3.8 times in the head; vestigial teeth 

 usually present on the premaxillaries, palatines, mandible, and tongue; body usually laterally 

 compressed. 



B. Premaxillaries longer than wide, usually oblique in position, never retrorse; lower jaw con- 

 tained not more than 2.3 times in the head; gill rakers relatively long and usually more 



than 31; maxillary seldom contained more than 3 times in the head Genus Leucichthys 



a. Gill rakers usually less than 40. 



1. Gill rakers usually more than 36; snout usually contained less than 3.5 times in the 



head and usually less than 2.2 times in the head depth; the head depth usually 

 contained more than 6.2 times in the head; mandible usually shorter than the 

 upper jaw zenithicus 



2. Gill rakers usually not more than 36; snout usually contained not less than 3.5 



times in the head and usually more than 2.1 times in the head depth; the head 

 depth usually contained not more than 6.2 times in the head; mandible usually 



shorter than the upper jaw reighardi dymondi 



aa. Gill rakers usually more than 40 and less than 54. 



b. Paired fins conspicuously black; body shape in side view ovate; fish commonly attaining 

 a length of 300 millimeters (12^4 inches) or more. 



3. Gill rakers usually 48-51; pectorals usually contained 1.4-1.6 times in the pectoral- 



ventral distance; ventrals usually contained 1.2-1.5 times in the ventral-anal 



distance nigripinnis regalis 



bb. Paired fins pale, or at least not conspicuously pigmented; body shape in side view ellip- 

 tical; fish not known commonly to attain a greater length than 250 millimeters (8 

 inches) . 



4. Gill rakers usually not more than 46; maxillary usually contained less than 2.6 times 



in the head; mandible usually superior and hooked hoyi 



5. Gill rakers usually more than 46; maxillary usually contained more than 2.6 times 



in the head; lower jaw usually equal to or shorter than the upper, never 



hooked artedi 



aaa. Gill rakers seldom less than 54. 



6. Fish attaining a length of more than 300 millimeters (12% inches); fins moderately 



pigmented nipigon 



94995—29—4 



