80 BULLETIN 18 9, UNITED STATES NATIONAL MUSEUM 



Family CLUPEIDAE: Herrings 



Body oblong or elongate, more or less compressed; belly compressed, 

 with bony scutes; mouth rather large, usually terminal, sometimes 

 superior; premaxillaries not protractile, maxillary with broad supple- 

 mental bones; teeth usually small, or wanting, variously arranged; 

 gill rakers generally long and slender; lateral line absent; scales thin, 

 smooth or pectinate, often lost in preserved specimens; dorsal fin 

 present (in Peruvian species), single, median or posterior in position; 

 no adipose ; caudal forked ; anal usually rather long ; ventral moderate 

 or small, sometimes missing; vertebrae about 40 to 55. 



KEY TO THE GENERA 



a. Anal fin rather short, with only about 15 to 25 rays; ventral fins inserted 

 under base of dorsal. 



b. Last ray of dorsal greatly produced, filamentous; dorsal with about 15 to 



18 rays; anal with about 17 to 22 rays; a dark shoulder spot usually 



present Opisthonema (p. 80) 



bb. Last ray of dorsal not especially produced. 



c. Back anterior to dorsal fin compressed and armed with bony scutes; gill 



rakers numerous, those of upper limb extending downward and forward 



across those of lower limb; ventral with 7 rays Ethmidium (p. 82) 



cc. Back rounded, not armed with bony scutes; ventral with 8 rays. 



d. Gill rakers very long and numerous in adult, about 100 on lower limb 

 in large specimens, those of upper limb extending downward and 

 forward across ones on lower limb; ventral scutes weak, sometimes 

 not definitely countable posterior to ventral fins; vertebrae about 



50 Sardinops (p. 86) 



dd. Gill rakers shorter and fewer, only about 30 to 35 on lower limb of 



first arch, those of upper limb not overlapping ones on lower limb; 



ventral scutes strong, about 26 to 32 present; vertebrae about 40 to 44. 



e. Rim of shoulder girdle with 2 small fleshy lobes on its vertical margin; 



upper limbs of first pair of gill arches with a forward projection 



between them, generally bearing from one to several short rakers on 



each side; no silvery lateral band present Harengula (p. 88) 



ee. Rim of shoulder girdle without fleshy lobes on its vertical margin; 

 no median forward projection between upper limbs of the first pair of 



gill arches; a broad lateral band present Lile (p. 90) 



aa. Anal fin very long, with about 45 to 65 rays; ventral fins, if present, inserted 

 in advance of dorsal. 

 /. Ventral fins present; origin of dorsal about equidistant from tip of mandible 



and base of caudal Ilisha (p. 91) 



ff. Ventral fins absent; origin of dorsal definitely nearer base of caudal than 

 tip of mandible. 

 g. Maxillary normal, not produced, ending under eye; anal verj- long, with 



about 60 rays Opisthopterus (p. 92) 



gg. Maxillary greatly produced, reaching gill opening in large specimens; anal 

 shorter (in Peruvian species), with about 45 rays. 



Odontognathus (p. 94) 



Genus OPISTHONEMA Gill, 1861 



Body compressed, back rounded, chest and abdomen w^ith a sharp 

 edge, bearing about 30 to 36 scutes; teeth absent; opercle with a deep 



