TABLE OF CONTENTS 



Page 



Introduction 1 



S3'stematic Part 1 



Family 24. Nonionidae 1 



Genus Nonion 2 



umbilicatulum 2 



crassulum 3 



depressulum 3 



pompilioides 4 



scaphum 5 



asterizans 6 



stelligerum 7 



germanicum 8 



sloanii 9 



grateloupi 10 



barleeanum 11 



labradoricum 11 



orbiculare 12 



pauperatum 13 



exponens 13 



Genus Nonionella 14 



turgida 15 



Genus Orbignyna 16 



Genus Cribrospira 16 



Genus Bradyina 17 



Genus Elphidium 17 



alvarezianum 18 



incertum 18 



var. clavatum 20 



striato-punctatum 20 



macellum 20 



crispum 20 



excavatum 21 



owenianum 21 



lessonii 22 



discoidale 22 



lanieri 23 



sagrum 24 



advenum 25 



var. margaritaceum 25 



poeyanum 25 



articulatum 26 



arcticum 27 



sibiricum 29 



Genus Polystomellina 29 



Genus Faujasina 2d 



V 



