THE TWAITE SHAD. 329 



Genus ALOSA. — Tongue and roof of the mouth desti- 

 tute of teeth ; upper jaw with a deep notch in the centre. 



A LOS A FINTA.* THE TwAITE SHAD. 









Specific Characters. — Distinct teeth in the upper jaw; a row of 

 dark spots along each side of the body. 



Description. — From a specimen thirteen inches and a half long. 

 The length of the head, that is, from the tip of the upper jaw to the 

 posterior margin of the gill-cover, exactly one-fifth the whole length 

 of the fish, caudal fin included ; depth of the body under the dorsal, 

 rather more than the length of the head ; operculum rounded at its 

 upper border, and nearly straight at its lower and posterior margin ; 

 basal line rather oblique, directing towards the last ray of the dorsal ; 

 suboperculum rather broad, slightly angular about the middle of the 

 posterior border. Colour of the back dusky blue ; sides lighter, with 

 green reflections ; bell}' silvery- white ; ventral and anal fins white ; 

 pectorals, dorsal, and caudal fins, dusky, the two latter minutely 

 spotted with dark brown ; upper part of the gill-covers and head 

 with beautiful yellowish-green reflections. Base of the first ray of 

 the dorsal fin exactly half-way between the point of the upper jaw 

 and the last ray of the anal fin ; the fourth and fifth rays the longest, 

 equalling the length of the base of the fin ; the last ray one-half the 

 length of the seventh, and rather longer than the two preceding ones, 

 giving the fin at the free margin a slight concave appearance ; all 

 the rays branched, except the first three or four, which are simple ; 

 caudal fin deeply forked, the longest ray equal to the length of the 

 head ; rays of the anal fin very short, the second and third the long- 

 est, considerably less than than one-half the length of the base of the 

 fin, the last two or three rays longer than the centre ones ; ventrals 

 commencing in a line under the sixth ray of the dorsal ; pectorals 

 rather small, and acutely pointed, the second ray the longest, equal 

 to the length of the base of the dorsal fin ; under jaw the longest ; 

 upper jaw with a deep notch in the centre ; end of the maxillary ex- 

 tending back as far as in a line with the posterior margin of the or- 

 bit. Eyes rather small, the diameter of which is rather more than one- 

 fifth the length of the head ; teeth very small, placed on the margin 

 of the upper jaw only ; none on the vomer, palatines, or tongue ; 

 lower margin of the maxillaries slightly roughened, but not a vestige 

 of a tooth on the lower jaw in the specimens now before me ; scales 

 large, very deciduous, extending half-way down the caudal rays; 



* Alosajinta, Cuv., Yarr. Clupea nlosa, Linn., Penn., Don., Jen. Shad, 

 Twaite Shad. 



