May, 1917] Silurian Fossils from Ohio 255 



His attention being called to his error privately by Barrande, 

 Beyrich figured the proper cephalon for his species in 1846, and 

 definitely designated the pygidium as the type. Corydocephalus 

 was not defined by Hawle and Corda until 1847 (Prodr. Mon. 

 Bohm. Tril., p. 139, pi. 7, fig. 4), and was based on the same 

 species, although the specimen he figured was regarded by him 

 as a new species (C flabellahis, sp. nov. Corda). Barrande 

 described the same species in 1846 as Lichas paJmata, owing to 

 Beyrich's error in his original description of Trochurns speciosus. 



Appendix: Two Species of Ordovician Fossils. 

 Lingulops cliftonensis, Foerste. Plate X, Fig. 9. 



1903. Lingulops cliftonensis, Foerste, Jour. Geol. vol. 11, p. 38. 



Pedicel valve 6 millimeters long, 3.5 millimeters wide, with an 

 elliptical outline similar to that of Lingulops norwoodi, James, from the 

 upper part of the Cynthiana formation, at West Covington, Kentucky. 

 The distinct part of the muscular area is thickened over its entire 

 surface, forming a low platform, with an elevation of about a sixth of a 

 millimeter along its anterior margin. The lateral margins of this 

 platform diverge at an angle of about 25 degrees. The oblique anterior 

 margins converge at an angle of about 85 degrees. The width of the 

 platfonn at its antero-lateral angles is 1.8 millimeters. The median 

 muscular scar, with parallel margins as in Lingulops norwoodi, has a 

 width of slightly less than half a millimeter. That part of the anterior 

 margin of the platform which is in front of the median scar curves 

 acutely forward and unites with the narrow median septum, at least 

 a millimeter in length, which extends forward to within less than a 

 millimeter from the anterior margin of the valve. Anteriorly, the 

 median muscular scar bears a faint median striation. Posteriorly, 

 the lateral muscular scars of the platform are limited at a point 2.5 

 millimeters from the acute anterior termination of the median scar. 

 Half a millimeter farther back lie the posterior margins of the three 

 crescentic lobes of the faint muscular impression characteristic of the 

 genus Lingulops. Of these lobes, the median is equal to or is slightly 

 larger than the two lateral lobes. The faint lateral impressions, on 

 each side of the platform, appear to be similar to those of Lingulops 

 norwoodi. 



From the preceding description it is evident that Lingulops 

 cliftonensis resembles Lingulops norwoodi much more closely 

 than was suspected at the time of the original description of 

 the species. The presence of the anterior median septum was not 

 known until recently, when the shell of the type specimen was 

 removed, so as to expose fully the natural cast of the interior of 

 the valve. From the latter species, Lingulops cliftonensis differs 



