GUELPH FAUNA IN THE STATE OF NEW YORK 171 



FIG. 



6-9 Four views of a partially crushed specimen which shows the 

 surface characters of the species and the form of the living 

 chamber. Fig. 9 is from a gutta-percha squeeze of the 

 mold and shows the hyponomic curve of the growth lines 

 on the ventral side. Rochester (Arey collection) 



10 Interior cast and mold of a specimen, retaining the siphuncle 



in position 



1 1 The siphuncle of the same specimen. X3. 



12-15 Four views of the most complete specimen observed. From 

 a sulfur cast of a natural mold in the rock 



16 Mold and cast, showing the thickening of the conch near the 



aperture 



17 Specimen which shows the hyponomic sinus of the growth 



lines on the ventral side and the contraction of the shell 

 near the aperture. From a gutta-percha impression of a 

 natural mold 



18 Internal cast of a large specimen, showing a broad and low 



living chamber and shallow septum 



19 Septal view of same 



All figures except 11 are natural size. Originals of fig. 10-10 

 are from the Lower Shelby bed (N. Y. State Museum). 



