FISHES OF THE GULF OF MAINE 385 



THE SILVER HAKES AND CODS. FAMILIES MERLUCCIID.E AND GADID.E 



The silver hakes and the cods are so closely allied that many European ichthy- 

 ologists group them in a single family. American practice, however, is to separate 

 them because of certain differences in the structure of the skull and ribs. They 

 are soft-finned fishes, lacking true spines at any stage in development (though in 

 one local species (the silver hake) the basal parts of the dorsal and anal fin rays are 

 so stiff as to feel like spines to the touch) but distinguishable from all other spineless 

 Gulf of Maine fishes by the fact that the large ventrals are situated under or in front 

 of the pectorals, and not behind them, as in herring, salmons, etc. They and their 

 relatives, the grenadiers (p. 467), are also separated from most of the typical spiny 

 rayed fishes by the structure of the skull. 52 



KEY TO GULF OF MAINE HAKES, CODS, ETC. 



1. Three separate dorsal and two anal fins; ventrals of ordinary form 2 



Two separate and well-developed dorsal fins 5 



Only one well-developed dorsal fin 11 



2. Lateral line black; a black blotch on the shoulder Haddock, p. 432 



Lateral line pale; no shoulder blotch 3 



3. Lower jaw projects beyond upper; tail forked; chin barbels very small or wanting 



Pollock, p. 396 



Upper jaw projects beyond lower; chin barbels large 4 



4. Ventrals narrow, prolonged in filamentous feelers as long as the rest of the fin; eye 



small Tomcod, p. 406 



Ventrals broad, their filamentous tips less than one-third as long as the remainder of 

 the fin; eye large Cod, p. 409 



5. The anal fin originates under or behind the point of origin of the second dorsal fin 6 



The anal fin originates considerably in front of the point of origin of the second dorsal 



fin Hakeling, p. 457 



6. Ventrals short; of ordinary form Silver hake, p. 386 



Ventrals very long and feeler-like 7 



7. First dorsal hardly higher than second, and none of its rays elongate or filamentous- 



Spotted hake, p. 455 



First dorsal much higher than second, with one or two long filamentous rays 8 



8. The ventrals do not reach back to the middle of the anal fin 9 



The ventrals reach nearly or quite to the rear end of the anal fin_ . Long-finned hake, p. 456 



9. Anal fin so deeply notched about midway of its length as to suggest two separate 



fins Blue hake, p. 444 



Anal fin continuous and of about equal height from end to end 10 



10. About 140 rows of scales along the lateral line from gill opening to base of caudal 



fin White hake, p. 446 



Only about 110 rows of scales along the lateral line Squirrel hake, p. 447 



11. The dorsal fin is preceded by a fringe of short rays and one long ray; the top of the 



snout as well as the chin bears barbels 12 



There are no isolated rays in front of the dorsal fin nor barbels on the top of the 

 snout disk, p. 462 



12. Top of nose with three barbels Four-bearded rockling, p. 458 



Top of nose with oly two barbels Three-bearded rockling, p. 462 



» The hypercoracoid bone lacks a foramen. 



