CAVOLINID^. 



19 



6. Styliola tenuis. 

 Creseis tenuis, Wahl. 



Fossil. 



7. Styliola ? ventricosa. 



Sheath straight at the back, slightly ventricose in front, tapering to 

 a point, nearly smooth, with faint sloping lines of growth and a 

 strong longitudinal furrow. 



Creseis ventricosa, Sharp, Quart. Jour. Geol. Soc. ii. 314, t. 13, f. 3. 



Fossil. Wenlock Flagrstone, Wales. 



8. Styliola? obtusa. 



Sheath short and conical, sides slightly curved towards a blunt 

 point, smooth (?), with a longitudinal furrow. 



Creseis obtusa. Sharp, I. c. 314, t. 13, f. 4. 



Fossil. Wenlock Rock, Wales. 



9. Styliola? gracillima. 



Sheath very long, straight and slender, tapering gently to a point. 

 Creseis gracillima. Sharp, I. c. 314, t. 13, f. 5. 

 Fossil. Wenlock Rock, Wales. 



10. Styliola? prim^va. 



Shell very long, linear, dilated towards the oral extremity, smooth 

 or with indistinct traces of longitudinal grooves. — Forbes. 



Sheath long, regularly tapering, smooth, with one (or more) longi- 

 tudinal groove. — Sharp. 



Creseis ? primaeva, Forbes, Quart. Jour. Geol. Soc. 1845, i. 146, f. 1 ; 

 Sharp, Quart. Jour. Geol. Soc. ii. 314, t. 13, f 2. 



Fossil. Palaeozoic Rock, Denbighshire. 



11. Styliola? Sedgwickii. 



Shell cylindrical, tapering, linear, marked with very numerous, fine, 

 regular, transverse striae ; aperture dorsally angular. 



Creseis? Sedgwicki, Forbes, Quart. Jour. Geol. Soc. 1845, i. 146, 

 f 2. 



Fossil. Palaeozoic Rock, Denbighshire. 



