330 TRANSACTIONS OF THE WAGNER FREE 



Solarium amphitermum n. s. 

 Plate 22, figures i6, i6 a. 



Older Miocene of Greensboro', Caroline Co., Maryland, Harris. 



Shell moderately elevated, large, solid, with a blunt periphery and about 

 seven whorls; nucleus sinistral, overturned and immersed in the succeeding 

 coil ; upper surface with a transverse sculpture of regularly spaced, impressed 

 lines in harmony with the flexuous lines of growth ; periphery marked by a 

 strong, broad, blunt rib cut by the impressed lines so as to carry squarish 

 nodulations. This is separated from a similar but less pronounced rib behind 

 by a deep, very narrow groove ; the surface hence to the suture may have one 

 or two fine obsolete spiral raised lines, or may show merely the transverse im- 

 pressed lines which sometimes gather at the appressed suture ; base flattened, 

 inside the rounded edge of the peripheral rib is a small beaded spiral ; umbili- 

 cus small, bordered by a stout rib with about twelve denticles, outside of 

 which is a smaller, undulated, flattish rib with a deep, narrow groove on each 

 side ; between this and the peripheral cord the surface is nearly smooth, or 

 with a few fine obsolete raised lines transversely sculptured with impressed 

 radiating lines strongest near the umbilicus ; aperture subquadrate, wider 

 than high, the end of the umbilical rib, when perfect, grooved and guttered. 

 Max. diam. of shell 18.5 ; of umbilicus 5.0; alt. of shell lO.O mm. 



This fine shell recalls 5". triliratum Conrad, from the Vicksburg Eocene, 

 which is smaller and more reticulated, beside differing in details of sculpture ; 

 S. trilineahnn Conrad, from the older Miocene of Maryland, is also smaller, 

 proportionately more elevated and has a sharp periphery. S. granulatum is 

 without the nearly smooth, broad band between the sutural and peripheral 

 sculpture. 



Before leaving this genus, it may be noted that I have not been able to 

 reconcile De Gregorio's figure of S. elaboraUim with any adult specimen of 

 the species I have seen, nor with his diagnosis ; this may be due to defects in 

 the figure, which appears to represent a very young shell much magnified ; 6". 

 cmlatura Conr., which De Gregorio refers to elaboratum as a synonym, is one 

 of the mutations of S. bellastriaUim. S. seinideciissatiini Guppy (Geol. Mag. 

 1874, p. 438) is probably a Solariella, but neither figure nor description is 

 sufficient to identify even the genus. Architectonic a Veatcliii and inornata of 

 Gabb, from the Chico upper Cretaceous of California, do not belong to the 

 SolariidcB, but should be referred to the Trochidce. S. antrosuni Conr. has- 

 not been figured, properly described or recognized since 1833 ; S. syrtalis 

 Conr. is a mere catalogue name never validated by description or figure ; 5. 

 striato-grajtulatum of Heilprin has been referred by Meyer to S. elaboratum, 

 but I have not examined the type ; ^. siipravemistiim De Gregorio has the 

 aspect, from his figure, of a Torinia, or at all events is not a typical Solarium. 

 S. stalagmium Conr. (Nov., 1833, -|- 5. elcgafts Lea, Dec, 1833, -\- S. perinum 

 De Gregorio, 1890) is a variable and beautiful species of Solariella, of which 



