TWAITE SHAD. 135 



of the fleshy portion of the tail, is shorter than the anal fin 

 in the Allice Shad, and has five rays less, beginning also 

 more forward : the tail deeply forked ; the caudal rays with 

 two thin membranous appendages on each side, parallel to 

 the seventh and thirteenth caudal rays, about an inch in 

 length by three- eighths deep ; all four membranes opening 

 from the centre, being attached by the outer edge only. 

 The scales of the body rather large in proportion than those 

 of the Allice ; the lateral line, as in most of the Clupeida, 

 scarcely perceptible. The abdomen strongly serrated. The 

 lower jaw the longest, with a few teeth anteriorly ; the 

 upper jaw with a deep central notch, and a row of small 

 teeth on the edge down each side. The breadth of the eye 

 equal to one-fourth of the length of the head ; the mucous 

 vessels on the surface of the gill-covers beautifully arbores- 

 cent ; the top of the head and back dusky blue, with brown 

 and green reflections in particular points of view ; from the 

 upper edge of the operculum a row of five or six dark spots 

 extend in a line backwards, the last generally the most in- 

 distinct, the number sometimes more than six ; the irides, 

 sides of the head and body, silvery white, with a tinge of 

 copper colour ; dorsal and caudal fins dusky ; pectoral, ven- 

 tral, and anal fins white. This species is immediately dis- 

 tinguished from the Allice Shad by possessing teeth, the 

 lateral spots, and the smaller anal fin. The fin-rays in 

 number are — 



D. 18 : P. 15 : V. 9 : A. 21 : C. 19. Vertebra 55. 



