THE FLAT-FISH FAMILY 



277 



ranean to the Shetlands, and the third from the English Channel 

 to Norway. The first and third are fairly common in the neigh- 

 bourhood of Plymouth, and in the estuary of the Clyde, and 

 punctatus has also been taken on the east coast of Britain and 

 east coast of Ireland. Norvegicus occurs on the west coast of 

 Ireland, and so also does unimaculatus. They are usually found 

 in sandy bays, and taken in shrimp trawls. But as they are 

 known, punctatus and unimaculatus at least, to have the power 

 and habit of clinging to the surface of rocks, and do not burrow 

 in soft ground, it is probable that they are much more abundant 



FIG. 129. Larva of the largest Top-knot, a little more than inch long, from a 

 preserved specimen ; after Holt. 



FIG. 130. Head of the specimen shown in 

 Fig. 129, viewed from the dorsal edge, and 

 showing the projecting spines in the region of 

 the ears ; after Holt. 



than they seem to be, but for the most part escape capture. 

 They adhere to the surfaces of the slate or glass sides of aquaria 

 by a constant waving motion of the hinder parts of the marginal 

 fins, which pumps out the water from beneath the body, and so 

 causes a pressure on the outside. They remain stationary thus 

 for hours, and from their dark colour are difficult to distinguish 

 on a dark surface. 



Breeding. Ripe eggs were obtained from a specimen of 

 unimaculatus 5 inches long; in June, in Loch Fyne. They were 

 buoyant and resembled those of the turbot, but were smaller ; 



