278 NEW UPPER CAMBRIAN FOSSILS — WALCOTT. 



DESCRIPTION OF PLATE XX. 



Page. 

 Fig. 1. Metoptomal peracAita 267 



1. Sketch of a specimeu iu a friable saudstone, the apex is broken 



away. 



Fig. 2. Metoptoma^ minneiskensis 267 



2. Side view and section of a typical 8i>ecimen. 



Fig. 3. Trochusl saratotjensis 268 



3. A nearly entire shell, drawn so as to show the form of the whorl 



and spire. 



Fig. 4. HyolUhec ncwioni 270 



4. View of the dorsal snrface and section of a typical specimen. 



Fig. 5. Platyceras texanum 268 



5. The outlines of this specimen are restored from two others, 



which preserve the missing parts. 



Fig. 6. Illwnurus ? dia 277 



6. Top, side, and front view of typical head. 



Fig. 7. Hyolithes curvatus 269 



7. Dorsal view of a nearly entire specimen. 



7a. Transverse section showing the acute ventral angle. 



Fig. 8. riatyceras hoyti 268 



8. Side view showing the external shell and also the cast of the 



interior surface. 



Fig. 9. Hyolithes corrugatus 270 



9. An elongate specimen and transverse section. 



Fig. 10. Connularia camhria 270 



10. View of a cast of the exterior snrface. 



Fig. 11. Hyolithes attenuates 269 



11. Dorsal side. 



Ua. Ventral side with transverse section. 



Fig. 12. Spirodentalium osceola 271 



12. A drawing made from a plaster cast taken in the sandstone 



matrix. 



DESCRIPTION OF PLATE XXI. 



Page. 

 Fig. 1. Ptychoparia hurnetensis 272 



1. The outlined portions are restored from other specimens. - 



Fig. 2. Ptychoparia connata 272 



2. Figure of iiortions of a head described. 



Fig. 3, 4, 5. Ptychoparia UanoenKin 272 



3. Head sho'wing the line of punctures on the line of the frontal rim. 



4. Head in which the punctures are absent. 



5. Head in which the imuctures are absent as well as the glabel- 



lar furrows. 



Fig. 6 Ptychoparia pcro 274 



6. A typical form of the Iiead of this species. 



Fig. 7. Ptychoparia mcira 273 



7. Top and side view of the specimen described. 



