xiv CONTENTS 



SECTION IX 



PAGE 



PHYLUM ECHINI I>ERMATA . . 346 



1. Examples of the Phylum ... . . 346 



i. Axf>'i-!<i* rii/if us and Anthenea flavescens .... 346 



ii. Strongylocentrotiis or Echinus . . 363 



iii. Crucumaria or Colochirus . . . . 369 



iv. Anti'il'ni I'nxacea ... 373 



2. Distinctive Characters and Classification . . . 377 



Systematic Position of the Examples . . . 380 



3. General Organisation . . 381 



SECTION X 



PHYLUM ANXULATA . . 403 



Class [. Chaetopoda . . . 403 



1. Examples of the Class . . . 404 

 i. JWyW.s dumerHii . . . 404 



ii. Lumliricns .... . . . 417 



2. Distinctive Characters and Classification . . 426 

 Systematic Position of the Examples . . . 428 



3. General Organisation . 429 



Appendix to Chaetopoda Class Myzostomida . . . 448 



Class II. Gephyrea .... . 450 



1. Example of the Class Sipuncidus nudus . . 451 



2. Distinctive Characters and Classification . . 454 

 Systematic Position of the Example . . 455 



3. General Organisation ... . 455 

 Class III. Archi-annelida . 462 

 Class IV. Hirudinea . ... 465 



1 . Examples of the Class Hirndo medicinal, is and H. quinquestriata 465 



2. Distinctive Characters and Classification .... . 474 

 Systematic Position of the Examples . 476 



.">. General Organisation .... . 476 



General Remarks on the Annulata . 481 



SECTION XI 



PHYLUM AHTHROPODA . . . . . . . 484 



Class I. Crustacea . 484 



1. Examples of the Class . 484 

 i. Ap\is or Lepidurus . . 484 



ii. Astacus fluviatttis . . . 498 



2. Bistinctive Characters and Classification . . 519 

 Systematic Position of the Examples . 524 



.".. General Organisation .... . 525 



Appendix to Crustacea Class Trilobita . 558 



Class II. Onychophora .. . 559 



Class III. Myriapoda . . 566 



1. Distinctive Characters and Classification . , 566 



2. General Organisation ... . 567 



