46 NORTH AMERICAN INDEX FOSSILS. 



Fig. 1243. Piloceras explanatory X K' ^'^^^ view of lower end of large specimen 

 with siphuncle protruding, and longitudinal section. (After Whitfield, Am. Mus. 

 Bull. ) 



12. P. wortheni Bill. (Fig. 1244.) Ordovicic. 



Smaller, less expanded, and with smaller siphuncle than preced- 

 ing; from 8 to 12 septa in an inch. 



Upper Beekmantown (H) of Newfoundland. 



Fig. 1244. Piloceras wortheni^ section of part of shell, with siphuncle filled by endosi- 

 phosheaths b, and cavity at a ; and view of detached siphuncle. (After Billings.) 



