243 



NOTES AND MEMORANDA. 



Some Notes on Plymouth Fishes. 



The Habits of the Cuckoo or Boar-fish For sorae time after 



I arrived iu Plymoutli at the begiuuiug of August I heard a 

 great deal about "cuckoos." The trawlers were constantly 

 talking of them, saying that their catches consisted almost 

 entirely of them, and it was not long before I saw speci- 

 mens of the fish which, among the fishermen, went by 

 this avian name. Even before I saw a specimen I found, on 

 referring to Day's ' British Fishes,' that the name implied 

 the Capros aper of Lacepede, the boar-fish of Couch. I 

 found specimens, soon after, knocking about the Barbican 

 in numbers, floating about Sutton Pool and Oattewater, or 

 cast up on the shores of these basins. Why the name 

 cuckoo is applied to these fish I have not discovered, but 

 Couch's name is due to a certain peculiarity in its snout. 

 The lower jaw, when the mouth is closed, slants upwards 

 and forwards and projects beyond the upper. When the 

 mouth is opened, and the lower jaw depressed, a system of 

 levers formed by bones at the sides of the mouth is moved 

 and causes the upper jaw to be protruded forwards. The 

 upper jaw is not firmly fixed to the skull, but connected 

 with it by ligaments and membranes which are very elastic. 

 Thus the depression of the lower jaw brings about a remark- 

 able protrusion of the upper, so that the whole mouth, when 

 opened, forms a narrow cylindrical membranous tube an inch 

 or more in length. As soon as the lower jaw is closed the 

 upper jaw is drawn back to its original position by the 

 elasticity of its ligaments. Thus the mouth region of the 

 " cuckoo," when the mouth is open, resembles somewhat the 

 snout of a boar ; hence the name boar-fish, and the specific 

 name aper. The mechanism of the jaws in the cuckoo is an 

 exaggerated development of an arrangement which occurs in 

 the herring and other fishes, and it will be of great interest 



