PLATE III 



Figure 12. Skenea planorbis. 



13. Rissoa minuta. 



14. Lacuna vinda. 



15. Lacuna neritoidea. 



16. Scalaria groenlandica. 



17. Turritella erosa. 



18. Aporrhais occidentalis. 



(A), immature specimen from below. 



(B), enlarged view of foot showing caudal appendage, 



(C), enlarged view of eye. 



(D), bifurcated end of proboscis. 



19. Turbonilla nivea. 



20. Menestho albula. 



