132 The Ottawa Naturalist. [Oct. and Nov. 



as a foot, with great rapidity, and prefers escaping in this way to 



swimming beneath the surface The fish are very nimble 



on land and difficult to catch. They use their muscular pectoral 

 fins to spring with, and when resting on shore the fore part of 

 their body is raised and supported on these." Other fishes in- 

 stead of using the paired fins for movement may use them as 

 anchors like some of the shore gobies, the lump-fish, and the 

 suckers {LiparididcB) whose ventral fins unite to form a broad 

 sucking disk under the body, enabling them to adhere to rocks 

 and stones with the firmest tenacity. 



A study of the nerve-supply and myology of the American 

 hake's hind pair of fins has not yet been made, but it would 

 yield some valuable results. Williamson's research on the 

 gurnard and Harrison Allen's account of the microscopic study 

 of the free rays in the Atlantic sea-robin {Prinotus) have shown 

 that these separated rays in the breast fins function as tactile 

 organs, and are really fingers. As I watched, some months ago, 

 the young hake pushing forward their ventral fins like long 

 fingers, poking into crevices with them, and touching particles 

 of food, or climbing over stones, and resting quietly upon these 

 fins just as a dog rests his head upon his paws, the conclusion 

 was irresistible that total change of function had taken place 

 with the change of form in these fins. It is necessary to add 

 that the eyes of these small hake are unusually large and 

 prominent, and the remark of Williamson does not apply in this 

 case that " in many fishes which have comparatively broad 

 heads, and in which the eyes are situated high up on the head, 

 some of the fin-rays of either the pectoral or pelvic fin are fila- 

 mentous. From the position of its eyes, the fish is unable to 

 see objects of prey close to itself It therefore depends on 

 organs of touch for aid in the capture of its food." 



These fishes illustrate, indeed, a change precisely the re- 

 verse of that seen in the bat, for their wing-like fins have been 

 converted into a kind of hand with separated fingers, extremely 

 sensitive as organs of touch, whereas the fingers of the bat have 

 been elongated and united by membrane to form a fin-like 

 wing. 



