INSTITUTE OF SCIENCE, PHILADELPHIA. 3O3 



Shell large, contorted, with an irregular coil and no internal laminae; 



Serp7ilorbis. 

 Shell large, with a turritelloid tip ; Vermicularia. 



Shell smaller, with internal laminae near the tip of the spire ; 



Petaloconchus. 

 Shell slit for access of water to the gills ; Siligiiaria. 



Genus SERPULORBIS Sassi. 

 Serpulorbis herculea Dall. 

 Lesueur's Walnut Hills Fossil Shells, pi. 4, figure 20, 1829. 



Later Eocene at Jarves' Spring, Hernando Co., Florida, Willcox. 



Tube large, rather thin, irregularly coiled, without external sculpture 

 except well-marked, more or less irregular incremental lines ; section of the 

 aperture circular. Length to diameter of aperture as about I to 15; maxi- 

 mum length of specimens about 300 mm. 



This shell might betaken for a Teredo tube, it is so thin and plain, but the 

 incremental striae point toward the Vernietidcs rather than anything else. Mr. 

 Willcox found this shell abundant at Jarves' Spring, many of the pieces reach- 

 ing a foot in length. Owing to the flinty character of this rock and the 

 tenuity of the shell, it is impossible to obtain complete examples. 



Serpulorbis granifera Say. 



Serpula grmiifera Say, Journ. Acad. Nat. Sciences, ist Ser. iv. p. 154, pi. S, fig. 4, 1824 ; 

 Miocene, Maryland. 



Latest Eocene at Martin's Station, Hernando County, Florida, Willcox; 

 older Miocene of Ballast Point, Tampa Bay and White Beach, near Osprey, 

 Florida, Dall; and at City Point, Va., Haldeman, and Maryland, Finch. 



This species, when in good condition and with normal sculpture, is readily 

 recognized. By some oversight it is omitted from both Conrad and Meek's 

 lists of Miocene fossils of the United States. 



Serpulorbis granifera var. tenera Dall. 



Chesapeake Miocene, Duplin County, North Carolina, Willcox. 



This differs from the creeping and decumbent form of the type in being 

 aggregated in masses, with the tubes nearly vertical, in having the surface 

 more distantly granular and the substance of the tubes much thinner, which, 

 as they mutually support each other, is not detrimental to the individuals com- 

 posing the mass. These tubes measure about 6.0 mm. in diameter at the 

 aperture and reach a length of over 83 ram. 



VernuttLS papidosus Guppy, from the Miocene of Jamaica, bears some re- 

 semblance to a single tube of this variety, but is more slender and with larger 

 granulations. 



