THE GOBIES, SUCKERS, AND BLENNIES 171 



indeed, colouring is scarcely diagnostic in many of these small 

 species. It has numerous small tentacles on the head. The 

 breeding of this species does not appear to have been made 

 the subject of special study, but there seems reason for accept- 

 ing the conclusion, with all reservation, of Mcintosh, that its 

 uniformly large eggs are demersal, like those of the other 

 oviparous blennies. 



The Gunnel, or Butter-fish [Centronotus gunnellus) has been 

 studied in the aquarium by Holt. It grows to a length of 

 nearly 1 2 in., the base of the dorsal fin being marked by white- 

 edged black spots. It has no tentacles on the head. Holt 

 found it spawning in the aquarium soon after Christmas, and 

 the parents took turns in coiHng their bodies round the eggs, 

 probably to keep them together. These eggs have been found 

 in the natural state in February in the rock-burrows of piddocks 

 with the parents on guard. The egg is demersal, and the larva, 

 when hatched out, journeys ofFto deeper water, returning later, 

 like the herring and sand-eel, to take up its residence close to 

 the shore. 



The Viviparous Blenny (Zcarces viviparus) is biologically 

 the most interesting of all. In place of depositing demersal 

 eggs, it brings forth well-developed young alive. It grows to 

 a length of 20 or 24 in., and is dark green in colour, with 

 brown tints, spots, and curved bands like arches. There is 

 a distinctive gap, or notch, in its dorsal fin. It seems to have 

 been confused in some parts of the country with the burbot, 

 a fresh-water relative of the cod, yet the only point of 

 resemblance is the long and almost scaleless body. The 

 prominent barbel on the lower lip of the gadoid should suffi- 

 ciently distinguish the two. 



The young blennies are born in winter in a well- 

 developed state. They at once display great activity, con- 

 cealing themselves from their numerous enemies by 

 burrowing under weeds and stones. So developed, indeed, 

 is the new-born larva, that it cannot possibly be compared 



