Xll 



CONTENTS. 



Chapter XXVII. INSECTA— continued. 



6. The formation of the germ-layers . ... 



7. Further development of the mesoderm 



Development of the body-cavity . ... 



8. The formation of organs . . ... 



A. Outer integument . . ... 



B. Endo-skeleton . . ... 



C. The nervous system . • . . . . 



D. The sensory organs . . ... 



The ocelli . . ... 



E. The tracheal system . . ... 



F. The alimentary canal and intestinal glands 



G. Heart . . . ... 



H. The musculature, the connective tissue, and the fat-body 



/. Genital organs . . ... 



II. Metamorphosis . . . ... 



1. The larval forms . . . ... 



A. Homomorpha . . ... 



B. Heteromorpha . . ... 



2. Development of the imago . . ... 



A. Development of the external form of the body . 



B. Development of the internal organs of the imago 



Hypodermis . . ... 



Musculature . . ... 



Intestinal canal . . ... 



The tracheal system . ... 



The nervous system . ... 



The fat-body . . ... 

 The ultimate fate of the phagocytes 



General considerations regarding the development of 



the imago in the pupa . ... 



III. Parthenogenesis, Paedogenesis, Heterogeny . ... 



IV. General considerations . . . ... 



Literature . . . . ... 



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Chapter XXVIII. 



GEXERAL CONSIDERATIONS 

 ARTHROPODA 



Formation of the germ-layers . 

 Appearance and further development of the organs 

 Nervous system 



Eyes .... 



Respiratory organs r . 

 Fore- and hind-guts . 

 Development of the enteron 

 Development of the mesoderm 

 Germ-band 



Embryonic envelopes, metamorphosis 

 Interpretation and relationships of the Arthropoda 

 Literature .... 



ON THE 



Subjects Index 

 Authors Index 



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433 



437 



