162 . THE BRITISH NATURE BOOK 



than any other, and measures some 3 feet in length. It is not oviparous, 

 but is said to produce young almost daily for several months a year. It 

 does great damage to nets and lines, and is equally hated by fishermen for 

 the damage it inflicts on the shoals of herring and other food fishes. Other 

 Dog-fish (such as the Rough Hound or LESSER SPOTTED DOG-FISH, Scyllium 

 canicula) are found off our shores ; the so-called " Mermaids' purses," yellow 

 horny envelopes with long tendrils, are their eggs, the tendrils being used to 

 attach the cases to weeds, thus ensuring their safety till the young have been 

 hatched out. A good deal of the flesh of the Dog-fish is prepared and sold 

 for food under other names. 



Of the smaller fishes found in the rock pools and close to the shore edge, 

 a few must be mentioned, because no reader can spend a holiday at the sea 

 without coming across them. 



THE BLENNIES, OR SHANNIES, 



are among the commonest, though they will escape observation by hiding 

 under sand or stones, and their curious mottled colour, green and yellow, 

 brown and black, serves to render them indistinguishable from their 

 surroundings when at rest. They are distinguished from other species by their 

 crimson-ringed eyes. The Smooth Blenny (Blennius pholis) has the peculiar 

 characteristic of being able to move its eyes independently of each 

 other, so that it may turn one upward as if to look out for enemies from 

 above, whilst the other surveys the bottom for food. It is generally found 

 in some small crevice, into which it retreats backwards at any alarm. It 

 has sharp teeth, and a large blenny (4 to 5 inches long) will hold on to your 

 finger almost like a marine bulldog. It is in this way that the fish will 

 seize a limpet which has slightly raised its shell from the surface of the rock, 

 and with a wrench will twist it off its resting-place and devour it. This 

 species has a short snout, and its head is not unlike a bulldog's, and there is 

 a clearly defined dent in the middle of the upper fin. 



THE GOBIES 



are generally common also, and can be identified by the formation of the 

 lower fins, which, being placed close together, form a kind of sucker, 

 enabling the fish to cling firmly to a rock or stone. The Black, or Eock, 

 Goby (Gobius niger), 5 or 6 inches when full grown, is coloured to 

 match the ground on which it rests. The male builds its nest under an empty 

 shell or seaweed, and, like the Stickleback, guards the eggs jealously until 

 they are hatched. The Little Goby (Gobius minutus) is only 2 or 3 inches 

 long, yellowish in colour, and marked with brown specks. 



The Spotted Gunnel, or BUTTER FISH (Centronotus gunnellus], is a deep olive 

 colour, with a row of black spots bordered with white under its one narrow 



