6460 Fishes. 



These six characters appear to afford conclusive evidence that 

 Lepidosiren is a fish, and not a reptile. 



But if we find the true or normal characters of a class thus, as it 

 were, dying out, and the more obvious and positive distinctions 

 utterly failing, shall we not conclude that one class thus gradually 

 merges in another exactly in the same way that a species has lately 

 been said to have no precise or definite limits ? I cannot admit the 

 position in either case, or the validity of the reasoning that thus breaks 

 down the barriers which nature appears to have set up. How numerous 

 are the opinions on record that the ornithorhynchus is something inter- 

 mediate between a stickler and a bird > and that it obliterates the line 

 of demarcation between the two. I cannot think so : I believe in 

 Nature's barriers, and I regard the difference from what is called a type 

 as the simple and inevitable consequence of diversity in structure ; in 

 fact it is but another mode of expressing a self-evident truism. The 

 Lamarckian hypothesis would, I suppose, regard the ornithorhynchus 

 as a suckler struggling to become a bird, the mud-fish a reptile strug- 

 gling to become a fish. All that I can see in these creatures is that they 

 are forms to which we are unaccustomed : had our knowledge of their 

 respective classes commenced with these two, and had the perch and 

 the monkey been the recently discovered rarities, we should have 

 experienced precisely similar difficulties in associating them with the 

 mud-fishes and water-moles. The belief in connecting links appears 

 to be gradually fading under the light of elaborate investigation ; 

 superficial similarities, as that of a bat to a bird, a whale to a fish, a 

 pangolin to a lizard, have their own signification and teaching, but the 

 more carefully these forms are investigated the more palpable does it 

 become that the distinctions philosophers have laid down are absolute 

 discoveries of what has always existed, not the mere creations of the 

 brain. In Entomology the multitude of species enables us to see this 

 more clearly : for instance the coleopterous type of structure gradually 

 fades away, becoming less and less pronounced at a variety of points, 

 but still the beetle is to be traced ; we found it nowhere so altered or 

 depauperated as to be mistaken for a member of some other division 

 of the world of insects. And thus the seemingly paradoxical mud- 

 fish is still a fish, although so reptilian in its superficial aspect as to 

 have induced such conflicting opinions. 



The remaining mud-fish at the Crystal Palace finally fell a prey 

 to that fatal disease of fishes, so well-known as the fungus : at first the 

 extremely minute filaments protruded about the base of the anterior 

 tendrils, but after a time the whole surface of the body was covered, 



