84 FOURTH FLOOR, SOUTHEAST PAVILION 



In the Toivcr of the Southeast Pavilion are displayed the fossil fishes 



which belong to a much earlier period than the mammals and reptiles, 



_ some of them having lived twentv to fiftv millions of vears 



Fossil ' * * 



Fishes a ^°° ^ an y °f these forerunners of backboned animals are 



quite unlike any living fishes and are probably only very 

 indirectly related to them; some were small, curiously encased in shells; 

 others, shown in the three cases in front of the visitor, attained large size 

 and were evidently formidable creatures. One of them in fact, Dinichthys, 

 shown in the middle of the gallery, was probably among the most destructive 

 creatures that ever lived in the sea. Its jaws were so strong that it could 

 crush a plate of bone as thick as one's hand. Such an actual specimen, 

 fractured in life and shewing the marks of "teeth" is shown in a neighbor- 

 ing case. 



The collection is so arranged that he who makes the tour can see the 

 principal kinds of fossil fishes and is able, in a measure, to outline the history 

 and pedigree of the entire group. He can trace the rise and fall of the 

 early plate-covered fishes; the era of the sharks which on the one hand 

 supplanted the earliest fishes and were in time replaced by the more efficient 

 lungfishes and ganoids; the age of ganoids when the waters were filled with 

 these enamel-scaled fishes; finally the age of the bony-fishes, or teleosts, 

 the multitudinous forms of to-day, the herrings, cods, perches, whose 

 methods of swimming, feeding and breeding are far more efficient than 

 those of any of their predecessors. 



Above the entrance are the jaws (models), spreading nine feet, of a 



huge fossil shark in which the actual teeth are arranged as in 

 Jaws ot t j ie s } iar k s Q f to-day, in the usual banks or rows — the teeth 



~, , in the hinder rows having served to replace those in front. 



Such a shark probably measured from seventy to ninety feet 



and its race may well have become extinct, when for various reasons the 



enormous volume of food necessary to support it could not be maintained 



within its range of sea. 



In the first alcove to the left, by the window, is a "fossil 



. * aquarium" in which a number of models of these earliest 



Aquarium ! 



fishes are arranged in a group, as though alive in the sea. 



In the next alcove are the early fossil sharks which superseded the tribe 

 of plated fishes just mentioned. These sharks had soft skeletons, simple 

 fins and a number of other primitive features which lead to 

 the belief that all of the higher fishes, and the higher back- 

 boned animals therefore as well, were descended from them, their simpler 

 structures becoming more complicated in many directions. In one of the 

 early sharks here exhibited, soft parts such as muscles and gill filaments, 

 have been petrified. 



