316 THE COMMERCIAL SEA FISHES OF 



I. Picked Dog-fish (Acanthias vulgaris). 



Names. Piked^ or spiked dog-fish ; common dog-fish ; spur 

 or bone-dog. Hoe (in Orkneys). Skittle-dog (male in Corn- 

 wall). 



Snout produced ; mouth slightly arched, with an oblique 

 groove on each side. Teeth. -In both jaws small ; with 

 their points turned so much on one side that their edges 

 become their cutting surfaces. Fins. Each dorsal fin 

 furnished with a spine in its anterior portion, while the 

 origin of the first dorsal is placed above the interspace 

 between the pectoral and ventral fins. Anal fin absent. 

 Colours. Superiorly of a slate-grey, while inferiorly it is 

 yellowish-white. Young examples have white spots along 

 the back and upper half of the body. Skin rough on the 

 hand being passed from behind forwards. 



Habits. A gregarious fish, which ranges through our 

 seas in search of prey ; occurring in the Orkneys in such 

 shoals that the fishermen have been known to load their 

 boats to the water-edge with them. So numerous are they 

 along our south coast that 20,000 have been taken in a 

 seine at one time. When captured it writhes itself across 

 the fisherman's hands, and if they are not attentive it 

 wounds them severely, and often dangerously. Yarrell 

 alludes to a school of these fish in 1858 which extended 

 in an unbroken phalanx on the east coast of Scotland for 

 20 to 30 miles. At the end of 1882 they were so numerous 

 off the Cornwall coast, as to impede, and in some instances 

 stop, the pilchard fisheries, owing to the injuries they 

 occasioned to the nets. 



Uses. Oil is made from the liver of this fish, its refuse 

 is useful for manure, and its rough skin used to be 

 employed for polishing wood. 



