GREAT LAKES COREGONIDS 



431 



Gill rakers on the first branchial arch : 

 Michigan, (41) 46-50 (52) .«» 

 Nipigon, (44) 48-51 (54). 89 



H/S: 



Michigan, 3.5-3.9 (4.1). 

 Nipigon, (3.4) 3.6-3.8 (4.3). 



Lateral-line scales: 



Michigan, (74) 80-87 (89). 

 Nipigon, (66) 70-77 (81). 



Pv/P: 



Michigan, (1.5) 1.6-1.8 (2.2). 

 Nipigon, (1.2) 1.4-1.6 (1.9). 



L/H: 



Michigan, (3.8) 4.1-4.4 (4.7). 

 Nipigon, (3.6) 3.8-4.1 (4.4). 



Av/V: 



Michigan, 1.2-1.5 (1.6). 

 Nipigon, (1.1) 1.2-1.5 (1.7). 



H/E: 



Michigan, 4-4.4 (4.6). 

 Nipigon, (3.5) 3.7-4.1 (4.3). 



L/D: 



Michigan, (3.2) 3.4-3.9 (4.3). 

 Nipigon, (3.1) 3.5-4 (4.5). 



The figures indicate that the Nipigon form has, on the average, somewhat more 

 gill rakers on the first branchial arch, many less scales in the lateral line, a larger 

 head and eye, and longer pectorals. In addition to fewer scales, there are also, on 

 the average, two less scale rows, so that around the body in front of the dorsal and 

 ventrals there are usually 40 to 42 90 rows, in front of the adipose and anus 31 to 33, 90 

 and around the caudal peduncle at its commencement 22 to 23. 90 The dorsal margin 

 of the pectoral is usually straight instead of decurved. Comparison of specimens in 

 Tables 41 and 47 shows a greater value in Nipigon specimens for the height of the 

 anal fin divided by its base length (AC). 



The race appears to be sufficiently distinct to merit designation, and I propose 

 to name it regalis. Specimen No. 57416 of Table 47 is designated as the type. It is 

 catalogued in the United States National Museum as No. 88354. 



The color in life is similar to that of the typical race, except that the back is not 

 pigmented so heavily and the underlying color is therefore less obscured. All the 

 fins are invariably conspicuously black; the membranes have a trace of sepia, strong- 

 est at the bases and becoming pinkish at the bases of the abdominal fins. In spirits 

 specimens seem to average blacker on the fins than the Lake Michigan specimens. 



Pearl organs probably are developed by the breeding males, but no specimens 

 taken in the breeding season have been examined. 



No specimens are available for the study of local variations. Only six specimens 

 smaller than 200 millimeters have been examined, and most of these are so imperfect 

 that their proportions have not been tabulated. The two of this class that have been 

 included in Table 47 show the same kind of differences when compared with longer 

 specimens, as the group of 151 specimens 200 to 290 millimeters in length compared 

 with 69 over 290 millimeters long. The first group showed, on the average, a slightly 

 larger head and eye, slightly longer paired fins, and less body depth than the longest 



Specimens smaller than 230 millimeters in length have been found to be sexually 

 immature, and often specimens 250 millimeters long were immature. 



81 These and other values given for Lake Michigan are based on an examination of 52 specimens ranging in length between 

 220 and 360 millimeters. 



These and succeeding figures for Lake Nipigon, unless marked otherwise, are based on an examination of about 230 specimens 

 ranging in length from 204 to 355 millimeters. 

 •° Twenty-six specimens. 



VARIATIONS 



fish. 



94995—29- 



10 



