PLATE XI a. 



Dalmanites v ' I ausmannia) pleuroptyx. 

 Page 28. 

 Fig. 1. A cephalon of average size, showing the general proportions, the crenulations on the frontal 

 border and the peculiar ornamentation of the cheeks. The left eye and a portion of the left 

 cheek spine are restored in the drawing. 



Lower Helderberg group. Near Clarksv, ly county. 



Pig. 'J. A cast of the under side of a pygidium regarded as belonging to this apei 



Oriskanj sandstone. Cayuga, Provinci of Ontario. 

 Fig. 3. A pygidium retaining must of the crust, and showing the normal charactei-a of the species. 

 Comiferous limestone. Lime Hock, Genesei county. 



Dalmanites (< Iorycephalus) dentatus. 



Page 58. 

 Fig. 4. A somewhat imperfect individual, but the most complete yet found, and the only one observed in 

 which the parts of the body are retained in conjunction. 



Lower Helderberg group. Port Jervis, Orange county. 

 Fig. y. A cephalon, nearly entire, showing the characteristic marginal ornamentation. 



Lower Helderberg group. Port Jervis, Orange count;/. 

 Fi«. 6. A pygidium, somewhat more flattened than that in fig. 4; showing the character of the surface 

 ornamentation and the bifurcate pleural ambulations. 



Lower Helderberg group. Port Jervis, Orange county. 



D.U.MAMIES (COUONI IIA '?) EMARGINATUS. 

 Page 40. 

 Fig. 7. A fragment of a pygidium, enlarged to two diameters, showing the broadly emarginate posterior 

 extremity, and the bifurcate, regularly tubercled ribs. 

 Schoharie grit. Schoharie, Schoharie county. 

 Fig. 8. Another imperfect pygidium. natural size, showing similar characters. 

 Schoharie grit. Scholiarie, Schoharie county. 

 These two are the only specimens of this species observed. 



Dalmanites (Hausmannia) concinnus. 



Page il). 

 Pig. 9. A small pygidium, enlarged to two diameters. 



Schoharie grit. Schoharie, Schoharie county. 

 Fig. 10. A larger pygidium, also enlarged to two diameters, showing the broad, flat angulations and the 



conspicuous posterior border. 

 Pig; 11. A profile of the same, similarly enlarged. 



Schoharie grit. Schoharie, Schoharie county. 



Dalmanites (Hausmannia) concinnus. var. serrula. 



Page 30. 

 Fig. 12. A very small pygidium, enlarged to three diameters. The specimen, in addition to the normal 

 characters of 1). com innus, has a row of spinules on the lateral margins. 

 Upper Helderberg group. North Cayuga, Province of Ontario. 



Dalmanites (Coronl'ua) myrmecofhorus. 



See Plates 13, 14, and 15. 

 Fig. 13. A large glabella, referred with doubt lathis species. 



Comiferous limestone. Schohar'u \. '), Schoharu county. 



