GREAT LAKES COEEGONIDS 



471 



VARIATIONS 



Racial variations. — Not enough specimens have been collected to determine 

 whether there is more than one race in the lake. There are no indications, however, 

 from the material obtained from several localities that such races, if they exist, are 

 marked by conspicuous external features. 



Size variations. — Only 13 specimens longer than 200 millimeters were obtained. 

 Five of these are extensively compared in Table 63 with five under 200 millimeters. 

 The meager data of this table indicate little, but it is likely that the usual changes of 

 growth obtain, namely, that large fish tend to have a proportionally smaller head 

 and eye and shorter paired fins. 



Individuals have been found approaching sexual maturity at 134 millimeters, 

 but some specimens below 157 millimeters show no indications of spawning during 

 the year. Beyond the last-named limit, all specimens were found to be maturing. 



comparisons 32 



A discussion of the differences between hoyi and zenithicus, reighardi, and nigri- 

 pinnis is given on pages 386, 408, and 432. 



From artedi and nipigon, hoyi is distinguished by its longer mandible, fewer 

 gill rakers on the first branchial arch, and longer maxillary. Certain of these charac- 

 ters are compared below: 



Gill rakers on the first branchial arch: 



hoyi, (40) 42-46 (48) , with 4 per cent more than 46. 



artedi, (41) 46-49 (53), with 74 per cent more than 46. 



nipigon, (54) 56-59 (66). 

 H/M: 



hoyi, (2.2) 2.3-2.4 (2.5), with 13 per cent more than 2.4. 

 artedi, (2.6) 2.7-2.8 (3). 

 nipigon, 2.5-2.7 (3.1). 



Hoyi is also much less pigmented than the others and has a larger head than 

 artedi. The specimens of nipigon are too large for comparison with those of hoyi 

 in this character. 



GEOGRAPHICAL DISTRIBUTION 



All the data for the specimens of the species that I have examined from Lake 

 Nipigon are given in Table 62 and are shown platted on the map of the lake in Figure 

 2. They are derived from the various apparatus that has been used on the lake. 

 The places from which bloaters have been collected are sufficiently scattered over 

 the lake to justify the conclusion that they occur throughout its extent where suit- 

 able ecological conditions obtain. 



DEPTH DISTRIBUTION 



The only nets employed by me in Lake Nipigon were the 2% and 2% inch 

 gill nets and in these noVioyi were gilled, but such specimens as they took became 



" Values in the comparison are given for all the collected specimens. 



