ESOCIDyE. 125 



DESCRIPTION. 



Colour. — Back tinged with blackish-green, which changes on the sides to light greenish- 

 grey, and on the belly to pearl-white : on the tip of each scale there is a bright speck having 

 the form of the letter v, and there are seven or eight longitudinal rows of oblong yellowish- 

 grey spots on the sides of the head, body and tail. The cheeks yield brilliant emerald-green 

 reflections ; the under jaw and gill-membranes are white : the irides greyish-purple with a 

 gold-yellow circle round the pupil. The dorsal and caudal fins are blackish- green, the former 

 marked with four patchy, longitudinal bands of oil-green, and the latter striped between the 

 rays with the same : the anal is pale greenish-grey with two or three horizontal bands of yel- 

 lowish-grey, or buff-orange : ventrals the same, with brownish-orange tips ; and pectorals 

 mostly brownish-orange shaded with grey. 



Scales thin, broadly oval, their outer edge semicircular, their covered portion deeply divided 

 by fissures into three or four lobes whose edges overlap *. The cheeks and upper half of the 

 operculum are scaly, the rest of the head is covered with smooth skin. The scales on the 

 sides, which are somewhat larger than those on the back, measure three lines and a half in 

 length by two and a half in breadth. There are 124 on the lateral line, and 36 in a vertical 

 row before the ventrals : a linear inch, measured on the sides, contains seven scales. The 

 lateral line is straight and rather nearer to the back than to the belly ; it is formed by a deep 

 notch in every third or fourth scale, and a groove in the subjacent one : there are several rows 

 of these emarginated scales on the back and sides, resembling lateral lines. 



Form. — Profile oblong or lanceolate. Body four-sided, the back broader and flatter than 

 the belly ; the vertical diameter of the fore and middle parts of the body is about equal to one- 

 seventh of its total length, caudal included : the transverse diameter is two-thirds of the ver- 

 tical one, and the body carries its thickness to near the anal and dorsal fins, where it thins off 

 into the compressed, tapering tail. Head forming one-fourth of the total length, caudal 

 included. Orbits lateral, close to the crown and midway between the tip of the snout and the 

 gill-openings. The space between the orbits is concave ; the snout is broad, rounded, and 

 depressed, and its tip is formed of a narrow cartilage covered by smooth membrane attached 

 to the end of the vomer, and lying between the intermaxillaries. There are upwards o* 

 sixty pores on the head, disposed round the orbits, on the preopercula, occipital suture, and 

 aloncr the limbs of the lower jaw. The mouth is capacious. The intermaxillaries are very 

 narrow, and are separated from each other by the somewhat dilated extremity of the vomer to 

 which they are articulated : they are the only portion of the upper lip which is toothed. The 

 labials have an oblong form, and are thrice the length of the intermaxillaries : their posterior 

 piece is very moveable and projects a little beyond the anterior one. The under jaw is longer 

 than the upper one by the thickness of the lip merely. The palate-bones are connected to the 



* In our English specimens there are only three lobes to the scales : in the Lake Huron one, most of the scales have 

 four lobes, and their texture is more compact. These variations are, perhaps, to be attributed to a difference in the age of 

 the fish. The Lake Huron specimen is larger, and may therefore be considered as older than the English ones with which 

 we compared it. 



