GUIDE TO CONTENTS. 



PAGE 



Introduction 259 



Pariolius (Footnote) 260 



Habits 261 



Distribution of the Pygidiidse (Plates XXXVI-XXXIX) 269 



Chronology 270 



Location of types 271 



Sources of the material examined 274 



Zoological position of the Pygidiidse 275 



Synonymy 275 



Limits of the family Pygidiidse (Plates XL-XLI) 276 



Key to the subfamilies and genera (Text figure 1) 278 



I. Nematogenys 279 



A', inermis (Plate XLII, figs. 1 and 2) 280 



II. Scleronema (Plate XXXVI, text figure 2) 280 



>S. operculatum : . . . (Plate XLIV, fig. 1) 281 



III. Hutcheria (Plate XXXVI, text figure 2) 281 



1. H. patagoniensis (Text figure 3) 283 



2. H. maculata (Plate XLII, figs. 3-5) 284 



3. H. titcombi (Plate XLIV, fig. 2) 284 



4. H. areolata (Text figure 4) 285 



5. H. burmeisteri (Text figure 5) 286 



6. H. macroei (Text figure 6) 287 



IV. Pygidium 288 



1. P. inarmoralum 290 



2. P. palleum 291 



3. P. tigrinum 291 



4. P. tenue (Text figure 7) 292 



5. P. corduvense (Text figure 8) 293 



6. P. spegazzinii 294 



7. P. borellii 294 



?8. P. eichorniarum (Plate XLIV, fig. 3) 295 



9. P. riojanum Berg 295 



395 



