119 



which terminate posteriorly in small beadlike tubercles, and ren- 

 dered more conspicuous by an ill-defined narrow encircling 

 depression in front of the suture. 



Dimensions. — Total length, 19; breadth, 9; length of aper- 

 ture, 13. 



Locality. — Upper beds at Muddy Creek (J". Dennant). 



Gexus Voluta. 

 synopsis of species. 

 Nucleus spherical, disproportionately large, columella plaits 

 3 or 4. 



Outer lip expanded, wing-like ; whorls tuberculated on the 

 shoulder. 1. V. Hannafordi. 



Outer lip not expanded ; whorls strongly costated. 

 Costag, 7 on last whorl, roundly angled. 



2. V. hejytagonalis. 

 Costse, 11 on last whorl, sharply angled. 



3. F. alticostata. 

 Costfe, 1 4 on last whorl. 4. F. Stephensi. 



Nucleus turbinated, crenulated ; spire-whorls costated and bear- 

 ing spinous scales at the shoulder ; columella plaits, 4. 



Ribs on posterior whorls, about 20 pairs. 5. F. McDonaldi. 

 Ribs on posterior whorls, about 9. 6. F uncifera. 



Nucleus papillary, smooth ; outer lip winged. 



Spire nearly as long as aperture ; nucleus small, with an 



erect tip. 7. F macroptera. 



Spire nearly half length of aperture ; nucleus large, blunt ; 



whorls medially angulated. 8. F Mortoni. 



Nucleus papillary, smooth ; outer lip not expanded. 



Shell sub-cylindrical ; surface finely wrinkled spirally. 



Last whorl with 14 inconspicuous transverse nodula- 



tions ; suture concealed 9. F. limbata. 



Last whorl with seven transverse tubercles ; suture 



exposed. 10. F conoidea. 



Shell oval-oblong to turriculate. 



Surface of anterior whorls smooth, without tubercles. 

 Pullus mamillate, large, its apex laterally im- 

 mersed. 11. F ancilloides. 

 Pullus papillary, blunt ; apex central. 



Spire attenuate, whorls slightly convex, 

 pullus small. 



Posterior whorls smooth. 



12. F McCoyii. 



Posterior whorls tuberculate. 



13. V. protorhysa. 

 Spire short, whorls convex, pullus large. 



14. F polita. 



