318 PISCES. 



two rows on the vomer, tongue, and pharyngeans : ven- 

 trals opposite the middle of the first dorsal ; the adipose 

 fin opposite the anal : branchiostegous membrane with more 

 than eight rays. 



41. OSMERUS. Two rows of teeth on each palatine, 

 the vomer with only a few teeth in front : ventrals opposite 

 the anterior margin of the first dorsal : branchiostegous 

 membrane with only eight rays : scales minute. 



42. THYMALLUS. Gape small : jaws, tongue, pala- 

 tines, and front of the vomer, with very fine velvet-like 

 teeth : branchiostegous membrane with ten rays : first dorsal 

 long and high : scales large. 



43. COREGONUS. Mouth as in the last genus, but 

 the teeth still smaller, sometimes entirely wanting : dorsal 

 not so long as it is high in front : scales very large. 



(3.) SCOPELUS. Gaye and gill-openings large: both jaws with 

 very small teeth ; the margin of the upper formed entirely by the in- 

 termaxillaries : tongue and palate smooth : branchiostegous membrane 

 with nine or ten rays : first dorsal answering to the space between the 

 ventrals and the anal ; second very small, with vestiges of rays. 



IV. CLUPEIDJE. jVb adipose Jin: upper jaw 

 formed in the middle by the intermaxillaries, 

 which are without pedicles; at the sides by the 

 maxillaries: body scaly. 



44. CLUPEA. Intermaxillaries short, and narrow ; 

 sides of the jaw formed by the maxillaries in three pieces, 

 and alone protractile : mouth with few teeth, sometimes 

 with none: abdomen compressed, the scales on the margin 

 forming a serrated ridge : gill-opening very large ; branch- 

 iostegous membrane with from six to eight rays. 



(1. CLUPEA.) Maxillaries arched in front: gape moderate; upper 

 lip entire. 



(2. ALOSA.) Upper jaw notched in fhe middle. 



45. ENGRAULIS. Snout projecting, and sharp- 

 pointed ; intermaxillaries placed beneath, and very small; 



