3^2 NEW YORK STATE MUSEUM 



PLATE 12 



Piloceras explanator Whitfield 



1 Enlargement of endosiphofunicle (part of section 2 of plate 11), 



showing its threefold branching and the angulation of the 

 endosiphosheaths at the points of intersection with the endosi- 

 phofunicle resulting from the suspension first of the outer 

 endosiphosheath by means of the endosiphofunicle and later 

 continuation of the latter to the next younger (more interiorly 

 situated) endosiphosheath. X3 



2 Shows similar features (enlargement of figure 3 of plate 11) 



of an endosiphofunicle, extending through two or more endosi- 

 phosheaths. X5 



3 Endosiphocoleon with its suspending endosiphofunicles (enlarge- 



ment of center of figure 5 on plate 11). X5 



4 Enlargement of part of figure 4 on plate 11, showing the angula- 



tion of the endosiphosheath at the point of its intersection with 

 the endosiphofunicle. X5 



5 Natural, slightly weathered transverse section . of a siphuncle, 



showing the undulating character of the endosiphosheath s, 

 probably due to endosiphofunicles. Natural size 

 Originals of figures 1-4 from the Beekmantown beds of Fort 

 Cassin Vt. ; of figure 5 from the same beds at Valcour N. Y. 



