THE MASCALONGE 1 93 



it meets its fellow of the opposite side in the median line. 

 This membrane assists in closing the gill-openings; and in 

 order that it can be open and shut readily, it is provided with 

 a number of parallel bony rays called branchiostegals, which 

 vary in number in different fishes. In the Mascalonge 

 there are from 17 to 19 on each side, while in the true Pike 

 or great northern Pickerel there are but 14 to 16, and in the 

 eastern Pickerel {Lucius reticulatus) and western or Grass 

 Pickerel [Lucius vermiculatus) 12 or 13. 



Just back of and below the eye is the cheek (pre-opercle), 

 and behind this is the gill-cover {opercle). In the Masca- 

 longe the lower half of both cheek and gill-cover is entirely 

 naked, while the upper half of both is more or less covered 

 with scales. In the Pike the scaling of the gill-cover is simi- 

 lar to that of the Mascalonge, but the whole of the cheek is 

 covered with scales, while in the eastern Pickerel and the 

 little western or Grass Pickerel, both gill-cover and cheek 

 are entirely clothed with scales. 



I have examined specimens of the Mascalonge from the St. 

 Lawrence; Lake Erie; Indian River, New York; the Upper 

 Mississippi; Eagle Waters of Wisconsin; Conneaut Lake, of 

 Western Pennsylvania; Chatauqua Lake, of Western New 

 York; and the heads of six specimens from the tributaries of 

 the Ohio River (one from Tennessee River), and find that 

 there are no important structural differences; they all agree 

 so well in regard to the number of branchiostegals, and in 

 the squamation of the cheeks and gill-covers, and in measure- 

 ments, that they must be considered as one and the same 

 species, with a geographical variation in coloration only. 



In the Mascalonge of the St. Lawrence basin the sides are 

 covered with roundish, dark gray or blackish spots, more or 

 less distinct, on a lighter colored, greenish or grayish ground. 

 These spots are more pronounced in the young, being then 

 quite dark and distinct, but in the adult they become more 

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