340 ILLINOIS STATE ACADEMY OF SCIENCE 



was, and the shark has been named from the spines, but 

 I am sure that it will take much study yet to settle de- 

 finitely its rightful affinities. 



If you wish the scientific names of these three types of 

 sharks you will find that they are Symmorium renif orme, 

 Orodus basilis, and Listracanthus, the first two derived 

 from the form of the teeth and the third from the spine. 



Still another shark that Professor Cope passed on 

 had small, very sharp teeth scattered over the palate, 

 which he named stylobasis. Needle like as the teeth were, 

 yet judging from the massiveness of the head it was of 

 considerable size. 



Aside from these more formidable types, which must 

 have been the terrors of that ancient sea, there were 

 several species of ganoids, an order of fishes that exist ir 

 our own day and have their chief representatives in the 

 gar pike and the sturgeon. One of the most beautiful 

 fossil fishes that I ever found was a ganoid, encased in 

 a glistening, white armor of scales, lapping up one 

 against the other, and all prettily decorated. It was five 

 inches long and an inch or so in height, and evidently was 

 as perfect as when the shale was sifted over it. This also 

 was sent to Professor Cope for determination. 



Another almost perfect ganoid shows scales and 

 characteristic tail with peculiar scale markings. One 

 often finds a single enameled scale, and even clustered 

 scales, and this is sufficient to show that such a fish exist- 

 ed. These little ganoids were elegantly shaped, and when 

 in schools must have made a brilliant spectacle. They 

 connect the remote past with the present. 



There are some remains that have not yet been figured 

 out. These are paddle-like remnants with rays attach- 

 ed to parts like those of a wrist, evidently belonging 

 to some creature that was neither fish nor reptile. More- 

 over one specimen shows the delicate backbone and im- 

 pression of some animal allied to the reptiles. 



We have then in this deposit a decided multiplicity of 

 life forms, some of which have relationship with the 

 present. I remember that on one occasion while at Spoon 

 river, thirteen miles east of this city, I was made aware 

 that a friend had caught a large bass, for his yell of ex- 



