xviii COMPARATIVE ANATOMY 



PAGE 



7. The Cikotjlatoky System . . . ^''5 



8. Fat Bodies — Luminous Bodies . ■ ^77 



9. The Respikatoht Organs . • ^''7 



10. Sound-producing Apparatus . 483 



11. Sexual Organs . *84 



12. Dimorphism — Polymorphism • 490 



13. Development and Life-history • 490 



14. Phylogeny . • 503 

 Literature .... . . 504 



Class IIL Araohnoidea sive Chelicerota 



Systematic lUview .... . 509 



1. Outer Organisation 511 



A. The Body . • 511 



B. The Extremities . . 516 



2. The Nervous System . , . 518 



3. The Eyes ... . .521 



4. Glands opening on the Outer Integument 522 



5. The Intestinal Canal . . . 523 



6. The Blood-vascular System . 526 



7. The Respiratory Organs . 528 



8. The Sexual Organs . . . 532 



9. Ontogeny . . . 537 

 10. Phylogeny . . 539 

 Literature . . 542 



Appendage to the Arthropoda 



Tardigrada . 544 



Literature . 545 



