PRESIDENT S ADDRESS. 



well known, but it was not until the year 1870 that the 

 existence of a living representative was brought to the notice 

 of science. 



The Teleostei which constitute the majority of the fishes of the 

 present day are the successors of the Ganoids. They do not 

 appear earlier than the chalk. By far the greater number are 

 found in the Tertiary Beds, mostly marine. Ganoids are now 

 reduced to two genera only, Lepidosteus and Accipenser. There 

 is no period of the earth's history in which there was a more 

 varied development of Fish. Pectinate, thin-scaled (Ctenoid) 

 and circular-scaled fish (Cycloid), occurred at the later stages 

 of the Mesozoic Age. 



The structure of the heart, brain, generative organs, and the 

 air-bladder of the Polypterus and Lepidosteus evidences a higher and 

 more Reptilian character than those of most other fishes. This 

 is, however, a question for the comparative anatomist, and not for 

 Palaeontology; Palaeontologists will point to the persistent 

 notochord and the heterocercal tail in the Palaeozoic and 

 Mesozoic fishes as evidence of an arrest of development or a 

 retention of embryonic characters in the fishes of early times. It 

 is remarkable that after all the mutations to which fish have been 

 subject, the edible forms, such as the Cod, the Turbot, the Salmon, 

 the Herring, became predominant immediately preceding the 

 advent of man. 



Elasmobranchii Rays and Sharks. These differ greatly in the 

 shape of the body. That of the Shark is long, and more 

 or less cylindrical, the gill-openings lateral ; the body of the Ray is 

 flat, the gill openings are on the underside and not lateral ; tail 

 slender. The Order is largely represented in every geological 

 formation. The Shark is exclusively carnivorous, and soars, so 

 to speak, in the higher regions of the seas, maintaining itself near 

 the surface by its large and powerful fins without the aid of an 

 air bladder. The habits of the Ray are quite in unison with the 

 form of its body ; it leads a sedentary life, moving slowly at the 

 bottom, and rising rarely to the surface. It lives at more moderate 

 depths than the Shark. 



