FLAT-FISH KS. 



45 



charncteristic of the Massachusetts fish, would here be regarded 

 as aberrant or abnormal. 



Three specimens of the Window Pane, or Sand Flounder, 

 Both us macalatus Mitchell, a rare species trom the Shippegan 

 coast, and of rather smiU size, had the following average: — 

 Dorsal rays 60, anal 49. Drs. Jordan, Gill)ert, and Evermann 

 give 65 and 52. Though the number of specimens was few, and 

 insufficient to furnish reliable data for a specitic average, the de- 

 crease is in about the same proportion as obtained in the other 

 species, and points to some general principle affecting them all 

 alike. 



The last species to be discussed is the Smooth Flounder, 

 Pleuronectes glaber Gill; and the table will be found to contain 

 twelve specimens collected in the Miramichi Bay and Baie des 

 Chaleurs. This flat-fish is less common than P. americanus, and 

 averages small, seldom exceeding a pound and a half in weight. 



So. 



7 



S 



9 



10 



11 



12 



No. 12 can be looked upon as aii example of individual varia- 

 tion, but the whole twelve average about 53 dorsal and 37 anal 

 rays. By reference to the authorities already cited the average 

 is seen to be 55 and 40; and though the decrease is less than in 

 the other species, it makes for the existence of some occult 

 influence modifying the type either here or in its more southern 

 habitat, or in both. 



If the reduction were seen in one species only, it might be re- 

 ferred to something peculiar to the life- history of that form now 

 or in the past; but such is not the case. It is general, affecting 

 all alike; and as they are fishes of similar range, life-habits and 

 nature, the cause must be general. Were the ancestral forniB of 

 these speeies known, the character and tendency of the variation 



