234 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvii. 



TT'. Pectoral fin with the lower rays 

 simple. 

 A'. Ventral rays I, 4; palatine teeth 

 usually present. 

 Y. Suborbital stay with a promi- 

 nent ridge; head with dis- 

 tinct ridges above; skin 

 prickly; preopercular spine 

 strongly hooked. 



TrdcJiidcrinns, 14. 



YY. Suborbital stay flat, without 



ridge; head rounded above. 



Cottu.s, 15. 



A'A^ Ventral rays I, 3; palatines 



mostly toothless. 



Uranidi'ii, 16. 

 WW. Pectoral fin with the rays all 

 branched; ventral rays I, 4. 

 liheopreshe, 17. 

 VV. Gill niendjranes free from the 

 isthmus or else forming a Ijroad 

 fold across it. 

 Z. Palatines without teeth. 

 a. Vomer with teeth. 



b. Dorsal spines simple, not fringed with tentacles; no tentacles on temporal 

 region. 

 r. Precpercle with three spines only, the uppermost straight, the third turned 

 downward; skeleton well ossified; lateral line developed, with or without 

 concealed plates. Lower jaw included; post temporal with one spine. 



Myoxocephalui>, 18. 

 cc. PreoiJercle with three si)ines; lower jaw projecting; post temporal with a 



double spine 3IegaJocottus, 19. 



ccc. Preopercle with four spines; the lowermost turned downward. 

 d. Nasal spines strong; bones of head firm; lower jaw included. 



e. Upper preopercular spine very long and straight; no slit behind fourth 



gill .1 inocottus, 20. 



ee. Upper preopercular spines curved. 



/. Ventral fins moderate, not reaching vent Porocoiius, 21. 



ff. Ventral fins very long; reaching past front of anal Argyrocotfus, 22. 



dd. Nasal spines obsolete; bones of head soft and spongy; lower jaw projecting; 

 lateral line reduced to scattered pores; vomer Avith teeth; deep water 

 sculpins, with feeble fins and reduced armature. 

 g. PTppermost preopercular spine long and sharp; dorsals separated. 



Zesticelm, 23. 

 gg. Uppermost preopercular spine short and concealed in the skin; 



dorsals continuous CoUunculus, 24. 



aa. Vomer and palatines toothless; upper preopercular spine stout, armed with 



antler-like processes; slit behind last gill small or vfajviin^. .Gymnocantlms, 25. 



bh. Dorsal spines each with a fringe of tentacles; ventral rays I, 3; a pair of mul- 



tifid flaps behind orbit Crossias, 26. 



ZZ. Palatines as well as vomer 

 with teeth; gill mem- 

 branes free from the 

 isthmus; last gill slit 

 small or wanting. 



