398 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



LL. Spinous dorsal well developed, depressible in a grooTc 

 — Scales minute or wanting ; premaxillaries non-pro-. 



tractile Scombrid/E, 74.. 



Scales of moderate size; premaxillaries protrac- 

 tile NOMEIDyE, 76 (b). 



LLL. Spinous dorsal little developed, or not distinguishable 



from the soft parts; no finlets. 

 M. Oesophagus without tooth-like process. Corypii.enid.e, 79. 

 MM. Esophagus with tooth-like process... Strom ateid.e, 77. 

 KK. Vertebne 25 (24-26); two free anal spines (sometimes obso- 

 lete). 

 N. Scales minute or obsolete, cycloid; tail widely forked. 



CARANGIDiE, 75. 



NN. Scales small, weakly ctenoid; tail little forked. 



POMATOMIDiE, 76. 



II. Scales well developed, mostly ctenoid ; * caudal peduncle not 



especially slender. 

 O. Pectoral with the lower rays detached and filiform ; 

 two short, separated dorsal fins; 

 head with muciferous system well 

 developed. 



Polynemid^, 68. 

 00. Pectoral fin entire. 

 P. Throat with two barbels; dorsals two; scales large. 



MULLID^, 90. 

 PP. Throat without barbels. 



Q. Skull cavernous; anal spines 1 or 2; lateral line 

 extending on the caudal fin; head 

 scaly; no teeth on vomer. 



SCI^NID^, 91. 

 QQ. Skull not especially cavernous. 

 R. Anal fin comx>aratively short, with less than 13 1 

 soft rays; vomer mostly with 

 teeth. {Perciform fishes.) 

 S. Scales caducous; dorsal fins two, the first short; 

 mouth very oblique. 



Apogonid^, 89. 

 SS. Scales adherent. 

 T. Aual spines 1 or 2; dorsal fins 2; pseudo- 

 brauchiai small or obsolete. 



Peucid^, 85. 

 TT. Anal spines 3}: or more (rarely obsolete). 

 U. PseudobranchifB small, covered by the 

 skin, or obsolete. 

 V. Vomerine teeth ; lateral line present. 



ELASSOMATID.E, 83 {h). 



VV. Vomerine teeth none ; lateral line obso- 

 lete Centrarchid/e, 1S4. 



UU. PseudobranchiiB well developed. 



W. Maxillary not slipping under i>reor- 

 bital for its whole length. 



* Small or wanting in some Uranoscopida;, Trichodont'idw, and Icosfeidw. 



t Except in some Sjjaridiv, Piiacanthidw, Cenirarchida', etc. 



t Obsolete in some Serranidcv; more than thi'ee in some CcntrarclddcB. 



