Jordan and Evertnann. — Fishes of North America. 425 



close to Clupea, with wliicli it may perhaps need to be reunited. It 

 seems to us best to regard the true herring, shad, alewife, and sardine as 

 distinct generic groups, although the characters of the dentition on 

 ■which Valenciennes chiefly relied for distinction have scarcely any value. 

 (nufia, opercle; Ad/3of, lobe.) 



a. Teeth in jaws present, those on tip of both jaws mostly persistent; adipose eyelid moderate; 

 peritoneum pale. ciiRysocHLOBis, 689 



aa. Teeth in jaws disappearing with age. 

 b. Peritoneum jiale. 



c. Head long, about 4 in length ; form rather elliptical. MEdiocrir, G90. 



cc. Head shorter and heavier, about i% in length ; body heavier ferward. 



fSEUDOHARF.NOrs, 691. 



66. Peritoneum black ; fins low. aiSTlVALis, 692. 



689. PO.MOLOBUS CHRISOCHLORIS, Rafinesque. 



(Skipjack ; Blue IIerrinq.) 



Head 3f ; depth 3|; eye shorter than snout, 4| in head. D. 16; A. 18; 

 lateral line 52; ventral scutes 20-|-13. Body elliptical, highest near the 

 middle, much compressed. Head rather slender and pointed, its upper 

 profile straight. Lower jaw strongly projecting, its tip entering the pro- 

 file; upper jaw emargiuate; premaxillary, and often tip of lower jaw, with 

 moderate-sized persistent teeth ; maxillary large, reaching to opposite 

 posterior part of eye. Eye large, well covered by adipose eyelid. Fins 

 moderate. Caudal peduncle slender, the caudal widely forked. Gill rakers 

 comparatively few, short, stout, and coarse, about 23 below the angle of 

 the arch. Opercles with radiating and branching striae. Brilliant blue 

 above; sides silvery, with golden reflections ; no dark spotsbehind opercle. 

 Peritoneum pale. Length 15 inches. Gulf of Mexico and Mississippi 

 Valley ; abundant ; resident in all the larger streams, and introduced 

 through the canals into Lake Erie and Lake Michigan. A handsome fish, 

 but worthless for food, as it is lean and bony. As ordinarily seen, it is 

 strictly a fresh-water species, but in the Gulf of Mexico, in rather deep 

 water, specimens of large size and excessively fat, are taken, (xpvaog, 

 gold; .^/wpof, green.) 



Pomolobtts chnisocliloris, Rafinesqtje, Ichtb. Oh., 38, 1820, Ohio River. 



Meletla stiarii, Cuvier & Valenciennes, Hist. Nat. Poiss., xx, 375, 1847, Wabash River. 



(Jltipea chrysochlori$, Jordan & Gilbert, Synopsis, 266, 1883. 



690. POMOLOBl S MEDIOCBIS (MitchiU). 



(Hickory Shad; Tailor Herring; Fall Herring; Mattowacca.) 



Head 4 ; depth 3|. D. 15 ; A. 21 ; lateral line 50 ; ventral scutes 20 -f 16. 

 Head comparatively long, the profile straight and not very steep, form 

 more elliptical than in the others, and less heavy forward. Lower jaw 

 considerably projecting ; upper jaw emarginate. Opercles rather less 

 emarginate below and l)ehind than in P. pscudoharengus. Fins low ; dor- 

 sal fin inserted nearer snout than base of caudal. Bluish silvery; sides 

 with rather faint longitudinal stripes. Peritoneum pale. Length 24 

 inches. Cape Cod to Florida ; rather common ; not highly valued as a 

 food-fish; not ascending streams to spawn, (medioois, mediocre.) 



