FIG. 



GUELPH FAUNA IN THE STATE OF NEW YORK 151 



Trematonotus alpheus Hall 



(See plate 6, fig. 1-9) 



20 Dorsal view of sculpture cast, showing peristome. Natural 



size. Rochester (Arey collection. Same specimen as plate 

 6, fig. i) 



21 Dorsal view of internal cast, showing dorsal perforations and 



smooth internal surface. Natural size 



23 Lateral view of same cast, showing umbilicus and inner volu- 

 tions. Natural size. Lower Shelby bed (N. Y. State 

 Museum) 



22 Fragment of a specimen with very strongly developed revolv- 



ing ridges and wide umbilicus. Natural size. Rochester 

 (Arey collection) 



