36 CLASS IV; ORDER Iv. 
covers three-leaved, scaly, serrated ; dorsal-fin 
spiny on the forepart ; scales (in most species) 
hard and rough. 
Ho.ocentrus, habit as Perca; gill-covers sca- 
ly, serrated and aculeated ; scales hard and rough. 
Bopianvs, (bedian,) habit as Perca; gill-cov- 
ers scaly, not serrated, aculeated ; scales smooth. 
Scomser, (mackrel,) body oblong, smooth, 
sometimes carinated by the lateral line ; finlets 
{in most species) above and below towards the 
tail. : 
GasTERosTEvs, (stickleback,) body somewhat 
lengthened ; dorsal-spines distinct ; ventral fins 
spiny ; abdomen carinated or shielded on the 
sides, and bony beneath. 
Mutuus, (surmullet,) head compressed, scaly : 
mouth bearded ; gill-membrane three-rayed ; bo- 
cy covered with large subdeciduous scales. 
Tricia, (gurnard,) head large, mailed and 
marked by rough lines ; gill-covers spiny ; gill- 
membrane seven-rayed ; finger-form processes (in 
most species) near the pectoral-fins. 
Tracnicuruys, head rounded in front: eye 
jarge ; mouth wide, toothless, descending ; gill- 
membrane furnished with eight-rays of which the 
four lowermost are rough on the edges ; scales 
rough ; abdomen mailed with large carinated 
scales. 
ORDER 4. ABDOMINALES. 
Gill-membranes with bony rays ; ventral-fins 
hack of the pectoral. 
Cositis, (loche,) mouth bearded (in most spe- 
cies) ; eyes situated in the upper part of the head: 
body nearly of equal thickness from head to tail ; 
