PLATE XXVI a. 



Stylonurus EXCELSN >li. 



Pages 156, 221. 

 See Plate 26. 

 Fig. 1. Tin' lower surface of the type specimen of Dolichocephala Lacoana, Claypole, showing- portions 

 of the cephalic appendages. These have all been pushed somewhat forward from their proper 

 position beneath the carapace, but as far as they are retained, appear to lie normally with 

 reference to one another. The restored parts, where their outline is not indicated by the 

 specimen itself, are drawn from figures of Stylonurus given by Woodward (Palseontographical 

 Society, 1872). 



A. A fragment of an appendage preserved as an impression upon the edge of the slab, and drawn 



in from a gutta-percha east It probably represents a portion of a long first pair of gnathopods. 



B. The right member of the second pair of gnathopods, showing the long basal joint, a portion of 



which is buried beneath the matrix, its denticulate mandibular edge, and the long recurved 

 palpus. A portion of the basal joint of the left member of this pair is also visible. 



C. A chelate terminal joint, possibly belonging to the first pair of appendages. 



D. The basal joint of the left member of the third pair, showing the double lamellate mandibular 



processes. 



E. A portion of the basal joint of the left member of the fourth pair, showing the mandibular 



margin. 



F. The left basal joint of the fifth pair of gnathopods, showing the broad surface, the conspicuous 



mandibular denticles, and the prominent surface of articulation. 



G. The position of the mouth. 



H. The outline of the carapace as if lies on the other side of the specimen. 

 Fig. 2. The terminal portion of the median dorsal ridge, drawn from the same specimen, showing tlw 

 ocelli, which are separated by a sharply impressed line and are slightly distorted. No evidence 

 of this feature is shown upon the specimen represented on plate 20. 

 Fig. 3. A portion of the carapace, natural size, showing the conspicuous, elongate tubercles, and, over the 

 surface where the thin crust has been removed, impressions of the sharply defined, semicircu- 

 lar squamse upon its lower side. 



Catskill group. Meshoppen, Wyoming county, Pennsylvania. 



