38 PALEONTOLOGY OF OHIO. 



same individual. In these plates the external markings are nearly oblit- 

 erated, slight traces, only, of the tuberculatiou remaining. 



Fig. 3 shows a similar plate, in which the surface-markings are some- 

 what more distinct, and the suture between the plate and the attached 

 spine is plainly visible. 



Fig. 4 gives an inside view of a plate which, like the preceding ones, 

 carries a spine, but its form is quite different. A number of such plates 

 have been found with those having the shape of Figures 1, 2, and 3, so that 

 I have supposed tliem all to belong to the same species. The spines 

 attached to the smaller plates were, apparently, without denticles. 



The plate represented by Fig. 5 has a different outline from either of 

 those before mentioned, but they are often found together, and tlie tuber- 

 culatiou, though stronger in Fig. 5, is essentially the same as in Fig. 3. 

 Fig 5 a represents a portion of the surface of Fig. 5, slightly magnified. 



Fig. 6 shows the inner face of a plate like Fig. 3, without its spine. 



Formation and Locality : Corniferous limestone, Sandusky and Delaware, Ohio. 



Genus ACANTHOLEPIS (uov. gen.). 



Among the many fish remains found in the Corniferous limestone, 

 there are none more puzzling than those to which the above name has 

 been given. They consist of tuberculated cranial or dermal plates, which 

 have a prevailing spatulate outline, but which differ very much among 

 themselves in form and consistence. Some are tliin and have somewhat 

 the appearance of large, elongated, unsymmetrical scales. Others are 

 stronger, and are produced into points that sometimes become spines. 

 The surface of all these plates is more or less tuberculated ; the tuber- 

 cules in some of them being strong and closely crowded, in others sparse 

 and fine. Whetlier these are body scutes or cranial plates remains to be 

 shown by farther discoveries. That they form parts of a somewhat ex- 

 tended series is shown by the fact, that, in some instances, two or more 

 are found occupying nearly their true position as regards each other. 



AcATfTHOLEPIS PTJSTULOSUS (n. Sp.). 



' Plate LVL, Pigs. l-'i. 



Cranial or body scutes, having a somewhat spatulate form, and attain- 

 ing, in some cases, a length of seven or eight inches, with a width of two 

 inches. These scutes were set contiguous to each otlier to form a defense 



