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 Cottidte, or the Gurnard 

 Family contains a few fresh-water species. 



COTTID^E: THE GURNARD FAMILY 



While some of the Cottid<e 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 (Cot t us gobio] 



FIN FORMULA. 

 First Dorsal : 6 to 8 spines. 

 Second Dorsal : 15 to 17 rays. 

 Ventral: 4 rays. 

 Anal: 13 rays. 

 Caudal : u or 12 rays. 



TEETH. 



Villiform, on the jaws 

 and vomer. None on 

 the palate. 



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. 



