20 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



dd" . Dorsal fin short to moderately long, with spines or with simple 

 rays; ventral fins with a spine and 2 to 5 soft rays. 

 /' ' . First dorsal with only about 2 to 7 spines (in Peruvian species) ; 

 head large, depressed in Batrachoididae and Uranoscop- 

 idae; mouth generally superior. 

 (]" . Gill openings restricted to sides; head broad, depressed; 

 ventral fin with a spine and 2 or 3 soft rays. 



Batrachoididae (p. 494) 



gg" . Gill openings wide, the membranes nearly or quite free and 



separate from isthmus. 



/i". Ventral with a spine and 5 soft rays; head depressed, at 



least partly covered with bony plates; soft part of 



dorsal and anal each with about 12 to 15 rays. 



Uranoscopidae (p. 357) 

 hh" . Ventral with a spine and 3 soft rays; head more or less 

 compressed, without bony plates; soft part of dorsal 

 and anal each with about 25 to 45 rays. 



Dactyloscopidae (p. 408) 

 //". First dorsal with about 10 to 30 spines or simple rays (in 

 Peruvian species) ; head not especially large, generally 

 compressed, 

 i" . Spinous and soft parts of dorsal about equal in length, or 

 latter slightly the longer, with 12 spines and 14 to 17 

 soft rays (in Peruvian species) ; premaxillaries not pro- 

 tractile; teeth in jaws in a single principal series, not 

 followed by a band of small teeth __Blenniidae (p. 383) 

 ii" . Spinous part of dorsal much longer than soft part, with 

 18 to 25 spines or simple rays and 11 to 17 soft rays (in 

 Peruvian species); premaxillaries generally protractile; 

 teeth in jaws in an outer series, followed by a band of 



small pointed teeth Clinidae (p. 394) 



hh. Ventral fins wanting. 



j" . Body long slender, snakelike; premaxillaries rudimentary or wanting. 

 k" . Caudal fin developed, confluent with dorsal and anal; tongue want- 

 ing; nostrils behind upper lip Muraenidae (p. 129) 



kk" . Caudal fin wanting, tail extending beyond dorsal and anal fins; 

 tongue present; one or both nostrils in upper lip. 



Ophichthyidae (p. 135) 

 jj" . Body not snakelike. 



/". Snout greatly produced, forming a tube with a very small mouth at 



tip; body encased in bony rings Syngnathidae (p. 152) 



U" . Snout not produced into a tube; body not encased in bony rings. 



m" . Upper jaw greatly produced, forming a sword; caudal peduncle 

 slender, with a strong lateral keel (very large sport and game 



fishes) Xyphiidae (p. 378) 



mm" . Upper jaw not produced into a sword. 



n" . Body very elongate, strongly compressed, band-shaped, coming 

 to a point posteriorly; dorsal and anal fins very long; caudal 



fin wanting Trichiuridae (p. 360) 



nn" . Body not very elongate, not band-shaped; dorsal short. 

 o" . Dorsal fin single, with soft rays only. 



p". Mouth moderately large; teeth small or wanting; gill open- 

 ing large, membranes not connected, free from isthmus; 

 caudal forked; body with normal scales; not capable 

 of inflation Clupeidae (see also n) (p. 80) 



