GREAT LAKES COREGONIDS 



493 



given locality. In the case of Saginaw Bay, where there has been extensive and 

 •continued operation of nets of a legally fixed mesh, it might be expected that the 

 average size of the fish taken would be reduced. My contention receives the support 

 of Doctor Van Oosten, also, who finds that most of the herring taken in Saginaw 

 Bay are very young fish. The adipose fin is a rudimentary character and is too 

 variable to have specific value. (See Table 71.) 



Typical examples of the Cutler form are so different from the typical herring 

 of Huron that they might readily be taken for a distinct species; in fact, they are 

 almost identical with the deep-water blackfin, nigripinnis, in those characters that 

 can be expressed numerically. They intergrade, however, with the typical herring 

 of the channel and behave exactly like them, so that there is no doubt that they 

 belong to the species group artedi. Furthermore, all those characters that have 

 varied to produce this form are those that a study of artedi elsewhere shows to be 

 fluctuating. All the herring of Lake Huron 225 millimeters or more in length are 

 compared below with 20 individuals taken at Cutler: 54 



H/S: 



Huron, (3.5) 3.7-4 (4.3). 

 Cutler, (3.7) 3.8-4 (4.2). 

 Pv/P: 



Huron, (1.7) 2-2.2 (2.6). 

 Cutler, (1.5) 1.6-1.7 (1.8). 

 Aw IV: 



Huron, (1.4) 1.6-1.8 (2.1). 

 Cutler, (1.1) 1.3-1.4 (1.6). 

 L/D: 



Huron, (3.5) 4-4.7 (5.4). 

 Cutler, (3.4) 3.5-3.8 (4). 



Crill rakers on the first branchial arch: 

 Huron, (40) 45-50 (53). 

 Cutler, (43) 44-47 (51). 

 Lateral-line scales: 



Huron, (68) 76-86 (98). 

 Cutler, (69) 71-77 (81). 

 L/H: 



Huron, (4) 4.3-4.6 (5). 

 Cutler, (3.9) 4-4.2 (4.3). 

 H/E: 



Huron, (3.7) 4-4.3 (5.1). 

 Cutler, (3.4) 3.7-3.8 (4). 

 H/M: 



Huron, (2.6) 2.8-3 (3.3). 

 Cutler, (2.5) 2.6-2.8. 



It appears from these figures that the Cutler form has a .longer head, eye, 

 maxillary, and paired fins, fewer lateral-line scales, and a much deeper body than the 

 artedi of Huron. The body is also much more compressed and, as has been stated 

 on page 492, much more pigmented throughout, and there are fewer scale rows. 

 The shape, as seen from the side, is elliptical as in the others, and the lower jaw is 

 usually equal to or somewhat shorter than the upper. Ten specimens are compared 

 extensively in Table 71 in all the characters that can be expressed numerically. 



Intergrades with the artedi form have been taken at Blind River on November 8, 

 1917, and at Kagawong, off Clapperton Island, on November 10, 1917. Those 

 characters in which the two forms differ are given for these specimens in Table 72. 

 The letter A follows the characters that approach the artedi type, the letter M those 

 that approach the manitoulinus type. 



Size variations. — Herring change but slightly in their systematic characters 

 with growth. A comparison of the principal proportional characters follows. The 

 lash are divided according as they are over or under 225 millimeters in length. In 

 the one group there are 215 individuals, in the other 133. Detailed figures for several 



« Jordan and Evermann (1911) say of the type of L. manitoulinus: "Type No. 64670, U. S. National Museum, a specimen 11 

 inches long from Blind River, North Channel, Lake Huron." 



