. Jordan and Evermann. Fishes of North America. 2883 



DD. Gill membranes joined to the isthmus; a sucking disk formed of 

 the ventral fins. 



E. Skin perfectly smooth ; spiuous dorsal not distinct. 



CLXXXIII, LIPARIDID^E, 2105. 

 EE. Skin with tubercles or spines, or else with a distinct spinous 



dorsal CLXXXII, CYCLOPTERID.E, 2094. 



CC. Breast without sucking disk. 



F. Gill membranes broadly attached to the isthmus. 



G. Ventrals completely united CLXXXVIII, GoBUDvE, 2188. 



GG. Veutrals widely separated; body depressed ; preopercle with a 



strong spine CLXXXVII, CALLIONYMID^E, 2184. 



FF. Gill membranes nearly or quite free from the isthmus. 

 H. Anal preceded by 2 free spines (these lost with age ; connected by 

 membranes in the very young).. CXXV, CARANGID^E, 895. 

 HH. Anal without free spines. 



I. Dorsal and anal tins followed by finlets . CXVIII, ScoMBRiDyK, 863. 

 II. Dorsal and anal without finlets. 

 J. Suborbital with a bony stay ; no free anal spines. 



CLXXIX, COTTID.E, 1879. 

 JJ. Suborbital without bony stay. 

 K. Mouth very large, nearly horizontal, the teeth sharp ; no pseudo- 



branchiu: CXCIII, CHIASMODONTID^:, 2291. 



KK. Mouth large, nearly vertical; body compressed; preopercle 



armed with spines CXCV, TRICHODONTID^E, 2295. 



AA. Gill openings small, behind, above, or below the pectoral fins, 



which are more or less pediculate. 

 L. Gill openings in or behind upper axil of pectorals; mouth small. 



CCXXIV, OGCOCEPHAODJ5, 2735. 



LL. Gill openings in or behind lower axil of pectoral; mouth large. 

 M. Head compressed; no pseudobranchia?. 



CCXXII, ANTENNARIID^E, 2715. 

 MM. Head depressed; pseudobranchise present. 



CCXXI, LOPHIID^E, 2713. 



III. VENTRAL FINS PRESENT, THORACIC OR JUGULAR, THE NUMBER 

 OF RAYS NOT DEFINITELY I, 5. 



A. Eyes unsyminetrical, both on the same side of head. 



B. Eyes large, well separated; edge of preopercle usually evident. 



CCXIX, PLEURONECTID.E, 2602. 

 BB. Eyes small, very close together; edge of preopercle hidden by 



skin ; mouth very small CCXX, SOLEID^E, 2692. 



AA. Eyes symmetrical, one on each side of the head. 



C. Ventral rays with or without spine, the number of soft rays more 



than 5. 



D. Caudal fin wanting; scales spinous . .CCXV, MACROURID.E, 2561. 

 DD. Caudal fin well developed. 



E. Tail isocercal, the vertebrae progressively smaller to base of cau- 



dal; ventrals jugular; no spines in any of the fins. 



F. Jaws and vomer with strong canines; second dorsal and anal 



deeply notched; no barbel.. CCXIII, MERLUCCIID^, 2529. 

 FF. Jaws and voiner without distinct canines; chin usually with a 



barbel CCXIV, GADID^:, 2531. 



EE. Tail not isocercal, the last vertebrae not reduced in size. 



G. Ventral rays about 15 ; dorsal fin single, elevated. 



CXXX, LAMPRIDID^E, 953. 

 GG. Ventral rays I, 3 or I, 5; dorsal very high. 



CXXXI, PTERACLIDID^E, 955. 

 GGG. Ventral rays I, 6 to I, 10; dorsal with spines. 



