20 



had been wiped out (at least the evidence we have says so), and 

 now of course it turns out that, after all, the old Coelacanth was 

 even more powerful than we knew. The ancient line still goes on, 

 after probably at least 30 million generations. Thirty million 

 generations, just think of it ! 



Another characteristic of Coelacanths is that although they 

 spread all over the world, they differentiated very little, that is, 

 even those widely separated remained much the same. For example, 

 fossils show that at one period there were Coelacanths living at 

 the same time on places as far apart as Greenland and Madagascar 

 that were so much alike that it is doubtful whether they were not 

 actually the same species. Over all those vast ages only about 

 twenty-five different genera are known, no less than ten appearing 

 in the Triassic, which was the time that Coelacanths reached a 

 climax in types and numbers. After that they seem to have de- 

 clined, but it is as well to remember that we do not know much 

 about those that lived in the sea, for fossils of purely marine 

 creatures are not easily formed or accessible. 



Over those vast ages the known Coelacanths were all much alike 

 in body form. The variations were few. Judging by their teeth, 

 they tried all sorts of diets, most must have been plain predators, 

 catching other fishes, but some obviously lived mainly on shell- 

 fish, having powerful molars and dental plates for crushing rather 

 than biting. Most of the extinct Coelacanths known from fossils 

 were quite small, a matter of 5-20 inches in length. But as will 

 readily be appreciated, the fossils are those of forms which 

 lived where they were most likely to yield fossils, and that was 

 chiefly in swamps. Water in swamps is not usually very deep, 

 and life there is restricted, so that most fishes in swamps are on 

 the small side. We almost certainly know more swamp Coela- 

 canths than any others. It is therefore by no means certain that 

 all Coelacanths of past times were small like that, and indeed in 

 quite recent years the remains of one of near 5 feet long have been 

 found in a rock stratum in Germany. It is plain that while we 

 have a wonderful fossil record, it must be very far from complete. 



So here we have the picture of the Coelacanths. This remark- 

 able type appeared more than 300 million years ago, and has gone 

 on, virtually unchanged as such things go, until the present time. 

 In that long time countless other types of fishy creatures evolved, 



