CONTENTS xvii 



PHYLUM AKTHBOPODA continued. PAGE 



Class III. Myriapoda . . 598 



1. Distinctive Characters and Classification 598 



2. General Organisation 600 



Class IV. Insecta . . .... 602 



1. Example of the Class Periplaneta orientalis or P. americana . 603 



2. Distinctive Characters and Classification 615 



Systematic Position of the Example 621 



3. General Organisation 621 



Class V. Arachnida . . 637 



1.* Example of the Class Euscorpio or Buthus ..... 638 



2. Distinctive Characters and Classification ..... 644 



3. General Organisation 646 



Appendix to the Arachnida the Pycnogonida, Linguatulida, 



and Tardigrada .......... 657 



Relationships of the Air-breathing Arthropoda .... 659 



SECTION XII 



PHYLUM MOLLUSCA ... 663 



Class I. Pelecypoda . . 663 



1. Example of the Class Anodonta and Unio 663 



2. Distinctive Characters and Classification 676 



Systematic Position of the Examples 678 



3. General Organisation . 679 



Class II. Amphineura .... . 694 



1. Distinctive Characters and Classification ..... 694 



2. General Organisation 695 



Class III. Gastropoda . 702 



1. Example of the Class Triton rubicundus 702 



2. Distinctive Characters and Classification 713 



Systematic Position of the Example 715 



3. General Organisation 715 



Appendix to the Gastropoda 736 



Class IV. Scaphopoda . 736 

 Class V. Cephalopoda . 



1. Examples of the Class 



i. Sepia 738 



ii. Nautilus pompilius ....... 754 



2. Distinctive Characters and Classification 766 



Systematic Position of the Examples .... .767 



3. General Organisation 768 



General Remarks on the Mollusca 780 



INDEX .... 783 



ZOOLOGY VOL. I. 



