GASTROPODA— TEREBRIDJE. 



799 



above, being marked by short, oblique, rib-like undulations gen- 

 erally wanting in the older whorls. Surface otherwise smooth, 

 except for oblique lines of growth. 



Chesapeakean of Maryland; corresponding beds of North 

 Carolina. 

 617. T. (Acus) curvilineata Dall. (Fig. 11 73, c-f.) Miocenic. 



Shorter and less tapering spire than preceding, whorls with 



c h 



Fig. 1 1 73. a, b, Terebra tinilineata ; c-f, T. {Acus) curvilineata, showing vari- 

 ations; g, T. curvilirata ; h, T. (Hastula) simplex; i, var. subliraia. (All from 

 Md. Survey. ) 



vertical ribs, the subsutural depressed spiral faint or obsolete. 

 In variety whitfieldi, Martin (Fig. 1173, c, d) the ribs are strong 

 but narrow and vertical, while fine sharp spirals mark the spaces 

 between the ribs. Aperture narrow. In variety dalli Martin 

 (Fig. 1 173, e) the ribs are obsolete except just below the suture; 

 while in the variety calvertcnsis Martin (Fig. 1173, f)> tne SUD ~ 

 sutural, depressed spiral is rather strong, the ribs being nodulated 

 upon the band thus produced. 



Chesapeakean of Atlantic coast from New Jersey south. 



