APPENDIX. 



79 



terminating in a wide-spreading border." (' 15th Report on State Cabinet of New- 

 York,' 1862, p. 107.) 



In Proetus Verneuili, as figured by Prof. Hall in his Illustrations of Devonian 

 Fossils (pi. xv, fig. 18), the lateral ribs extend partly across the border, forming 

 a line of marginal tubercles, but there is no crenation of the edge. This is the 

 nearest approach to the appearance described by Prof. Meek (loc. cit.) with which 

 I am acquainted. 



It follows, therefore, that with the single possible exception of Phillipsia 

 Lodiensis, as described by Prof. Meek, no Trilobite has been announced from the 

 American Carboniferous rocks in which the pleural ridges of the pygidium extend 

 beyond the border. The occurrence, therefore, of the form (Dalmanites ? Cuya- 

 hoga;) figured and described below (fig. 6) is of considerable interest to palaeontolo- 

 gists. It was found in the Cuyahoga Shale, the uppermost member of the Lower 

 Carboniferous system in Northern Ohio. 



PlG. 4. GriffitUdes 5. Phillipsia 6. Dalmanites ? Cuyahoga, Claypole 7. Phillipsia 8. Brachymetopus 



globiceps, De Knu. Derbiensis, Martin (twice nat. size). Lodiensis, Meek discors, M'Coy. 



(twice nat. size). (twice nat. size). (twice nat. size). (five times nat. 



size). 



Pygidia of species of Carboniferous Limestone Trilobites, Griff. globiceps, Ph. Derbyensis, Ph. Lodiensis, and Brack, discors., 

 compared with the pygidium of Dalmanites Cuyahoga. 



Dalmanites ? Cuyahoga, Claypole. Geol. Mag., Decade iii, vol. i, p. 306, 1884. 



(Woodcut, Fig. 6.) 



Head and thorax unknown. Pygidium about as broad as long, exclusive of 

 the spinous processes to be mentioned below; distinctly trilobate. Middle lobe 

 occupying a full third of the breadth, extending nearly to the hind extremity, 

 distinctly separated by a furrow from the lateral lobes, and containing eleven or 

 twelve ridges or partial rings. Lateral lobes as wide as the medial lobe, their 

 segments or ribs produced for the most part about half their length beyond the 

 marginal line formed by their union and ending in points, the third, seventh, and 

 ninth produced to double the distance and having the appearance of spines. The 

 third pair curve backward so that their points are level with the hind end of 

 the pygidium. No marginal tract. "Whole surface set with tubercles, of which 

 there are five on each of the three parts of the first ring, the number gradually 



11 



