Dr. /. S. Newberry on American Fossil Fis/ie. 



77 



These spines are very characteristic of the horizon of the Cor- 

 niferous Hmestone ; having been found in Indiana, various lo- 

 calities in Ohio, in New York and at Gaspe, C. E. Though pre- 

 senting some anomalous characters, (among which the most 

 remarkable ia their want of symmetry, being rights and lefts), it 

 is hardly possible they can be anything else than the defensive 

 spines of placoid fishes. Their dense bony structure, enamelled 

 surface, and their rough and irregular bases, would seem to prove 

 that like the fin-spines of many sharks and rays they had been 

 implanted in the integuments without articulation. Possibly 

 they were the first rays of the pectoral fins, which would account 



luf their being m pai 



find the bases exhibiting some marks of their articulation 



that case we should expect to 

 " - 1 the 



thoracic arch. Some of these spines are more than : 

 length, double-edged and very sharp, constituting most formida- 

 ble weapons of attack or defense. My friend Dr. Wm. Stimpson, 

 whose knowledge of Crustacea is so minute and so general, is 

 decidedly of the opinion that they could not have belonged to 



Teeth 

 which they radiate 

 section toward the 

 summit, are some- 

 what compressed 

 below, and expand 



ral prominent roots 

 or tuberosities, of 

 which the most con- 

 spicuous are on the 

 side toward which 

 3 curved, 

 ey have a cen- 

 t cavity extend- 

 ■ iarly 



hepoi. 

 ihey 



pomt, surrounded 

 Py dentine, simple 



in structure, the ex- , , 



^rnal surface covered by a layer of smooth and polished enamel. 

 , These are apparently the teeth of sharks, generally detached 

 from the cartilaginous iaws, and scattered through the limestone 

 m which thev nrA fnnnH • a TOW of them, however, occasionally 

 as is the case with Helodus, Orodus, 



