74 BRITISH FRESH-WATER)} FISHES 
strange sucking-fish (Echeneis), which, being a shocking 
bad swimmer, attaches itself by this apparatus to the bodies 
of larger fish or to ships and boats, and thus secures a free 
passage from place to place. 
Most of the fishes of this sub-order are exclusively 
marine, but the thirteenth family—Cottide, or the Gurnard 
Family—contains a few fresh-water species. 
COTTIDA:: THE GURNARD FAMILY 
While some of the Cottide are of extravagant and complex 
beauty, like the gurnards, others are of ignoble and even 
repulsive aspect, like the father lasher. The bones of the 
head are more or less armed with spines, and where two 
dorsal fins are present, the soft posterior dorsal and the 
anal fins are more developed than the spinous first dorsal. 
All the members of this family are distinguished by dispro- 
portionately large heads, and, although amply provided with 
fins, they are but indifferent swimmers. 
The Bullhead, or Miller’s Thumb (Cottus gobio) 
Fin FORMULA. TEETH. 
First Dorsal: 6 to 8 spines. Villiform, on the jaws 
Second Dorsal: 15 to 17 rays. and vomer. None on 
Ventral: 4 rays. the palate. 
Anal: 13 rays. 
Caudal: 1% or 12 rays. 
The only representative of the Gurnard Family in British 
fresh-waters owes its popular name of miller’s thumb to its 
broad, depressed head, in which a fanciful resemblance has 
been traced to the form supposed to be imparted to the 
thumb of a miller by the constant use of that organ in 
testing the evenness of the flour as it falls from the mill 
spout. 
ee 
