CHELONIA 



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thought that the specimen, notwithstanding its monstrous size, 

 represented a very primitive kind of turtle, and gave to it the name 

 Protostcga gigas, meaning gigantic first roof! The late Professor 

 George Baur, to whom paleontology owes so much, showed that, 

 far from being a primitive turtle, Protostega was really one of 

 the most specialized types of the order. Professor Cope's account 

 of the discovery of the specimen is of so much interest that it 

 may be quoted here: 



"In the very young tortoise or turtle the ribs are separate, as 

 in other animals. As they grow older they begin to expand at the 

 upper side of the upper end, and with increased age the expansion 

 extends throughout the length. The ribs first come in contact 

 where the process commences, and in the land tortoise they are 

 united at the end. In the sea-turtles the union ceases a little 

 above the ends. The fragments of the Protostega were seen by 

 one of the men projecting from a ledge of a low bluff. After 

 several square feet of rock had been removed, we cleared up the 

 floor and found ourselves well repaid. Many long, slender pieces 

 of two inches in width lay upon the ledge. They were evidently 

 ribs, with the usual heads, but behind each head was a plate like 

 the flattened bowl of a huge spoon, placed crosswise. Beneath 

 these stretched two broad plates, two feet in width, and no thicker 

 than binder's board. The edges were fingered and the surface 

 was hard and smooth. All this was quite new, among fully grown 

 animals. Some bones of a large paddle were recognized, and a 

 leg bone. The shoulder-blade of a huge tortoise came next, and 

 further examination showed that we had stumbled on the burial 

 place of the largest species of sea-turtle yet known. But the ribs 

 were those of an ordinary turtle just hatched, and the great plates 

 represented the bony deposit in the skin, which, commencing 

 independently in modern turtles, unite with each other at an early 

 day. But it was incredible that the largest of known turtles should 

 be but just hatched, and for this and other reasons it has been con- 

 cluded that this 'ancient mariner' is one of those forms, not un- 

 common in old days, whose incompleteness in some respects points 

 to the truth of the belief that animals have assumed their modern 

 perfection by a process of growth from more simple beginnings." 



