684 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY - IV. 



m. Palatine teeth noiio. 

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



times forming a fold across it. 

 o. First dorsal spine not elevated. 



p. Preorbital strongly cavernous; intestinal canal 

 short ; spines of head short ; fresh 

 water ................ TRIGLOPSIS, 369. 



pp. Preorbital little can vernous; iutestial canal short; 

 spines of headlong; marine. (Snbgemis 

 Oncocottns) ................ COTTUS, 367. 



ppp. Preorbital not cavernous; intestinal canal elon- 

 gate; lateral .line, with a series of large 

 bony plates ........... ENOPHRYS, 370. 



oo. 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, :'.?-'. 



mm. Palatine teeth present. 



q. Gill-membraues joined to the isthmus, sometimes 



forming a narrow fold across it. 

 r. Skin perfectly smooth ; preopercular spine with 

 antler-like processes; spinous dorsal 

 short, entire ........ LKPTOCOTTUS, 373. 



rr. Skin with bands of rough scales ; preopercular 

 spine simple; spinous dorsal long, eniar- 

 ginate ........... HKMILF.PIDOTUS, 374. 



qq. Gill-membranes entirely 1'ree from the isthmus. 

 . Sides of back with a baud of rough scales; 

 ventral fins very long, armed with set:e. 



MELLKTICS, 375. 



89. Sides of back without band of scales. 

 t. Veutrals I, 5; spiuous dorsal long. 



SCOHP.ENICHTIIYS, 376. 



tt. Ventrals I, 3; spinous dorsal short. 



OLIGOCOTTUS, 377. 



II. Skin everywhere rough with villiform prickles: lirst dorsal 



elevated in front; head small, with ver- 

 tical cheeks. 



u. Gill-membranes free from the isthmus; 

 veil Ira Is small .......... I5l.rr>-i \-. ::;*_ 



uu. Gill-membranes united to the isthmus; 

 ventrals well de\ doped. 



N \rirciri ins, :57'.. 



gg. Gill-opening restricted to the space above the upper edge of th<> i>;is<> 



of the j)ectoral; skin everywhere with 

 bifid or trilid prickles. (Illtamphocot- 



v. Snout produced ; month very small; no 



teeth on vnniei or palatines; head ele- 

 vated, with two bony ridges. 



RlIAMPUOCOTTUS, 380. 



