G84: CONTKIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



m. Palatine teeth noue. 



n. Gill-membraues more or less joined to the isthmus, some- 

 times forming a fold across it. 

 0. First dorsal spine not elevated. 

 J). Preorbital strongly cavernous; intestinal canal 

 short ; spines of head short ; fresh 



water Triglopsis, 369. 



]ip. Preorbitallittle canveruous; iutestial canal short; 

 spines of headlong; marine. (Subgenus 



Oncocotfus) CoTTUS, 367. 



PI)}}- Preorbital not cavernous; intestinal canal elon- 

 gate; lateral line with a series of large 



bony plates Enophrys, 370. 



00. First dorsal spine elevated; skin perfectly smooth; 



intestinal canal short. .Liocottus, 371. 



nn. Gill-membranes free from isthmus ; sides below with 



oblique series of minute prickly scales; 



series of plates along back and along 



lateral line Triglops, 372. 



mm. Palatine teeth present. 



q. Gill-membranes joined to the isthmns, sometimes 

 forming a narrow fold across it. 

 r. Skin jierfectly smooth ; preopercular spine with 

 antler-like processes; spinous dorsal 



short, entire Leptocottus, 373. 



rr. Skin with bands of rough scales ; preopercular 

 spine simple; spinous dorsal long, emar- 



ginate Hemilepidotus, 374. 



qq. Gill-membranes entirely free from the isthnuis. 

 8. Sides of back with a baud of rough scales; 

 ventral fins very long, armed with setaj. 

 Melletes, 375. 

 8S. Sides of back without band of scales. 

 (. Veutrals I, 5 ; spinous dorsal long. 



SCORPJDNICHTHYS, 376. 



tt. Ventrals I, 3 ; si)inous dorsal short. 



Oligocottus, 377. 

 U. Skin everywhere rough with villiform prickles; first dorsal 

 elevated in front; head small, with ver- 

 tical cheeks. 

 M. Gill-membranes free from the isthnms; 



veutrals small Blepsias, 378. 



MM. Gill-membranes united to the isthmus; 

 ventrals well developed. 



Nautichthys, 379. 

 gg. Gill-opening restricted to the space above the upper edge of the base 



of the pectoral; skin everywhere with 

 bifid or trifid prickles. {IlhampJiocot- 

 tir.ae.) 

 V. Snout produced ; mouth very small ; no 

 teeth on vomer or palatines; head ele- 

 vated, with two bony ridges. 



Rhamphocottus, 380. 



