iv CONTENTS. 



LIIAPTER IAI.K 



SBC 4. 'riieDcvclopmentoftheAlimentaryCan.il - - 421 



(i. In the Embryo - - 4 21 



I'. After Development - - 426 



XII. Tin, NERVOUS SY>TKM 433 



Si.c. i. Anatomy of the Nerve Centres 433 



(i. The Thoracic Nerve Centre of the Blow-Fly Imago - 435 



b. General Structure of the Brain in the Arthropoda - 440 



c. Details of the Structure of the Brain of the Blow-Fly 



Imago - 45 



d. The Sensory Ganglia - - 467 

 Si;c. 2. The Physiology of the Nervous System in Arthropods 473 



3. The Development of the Nervous System - 479 



XIII. Tm; SENSES AND SENSORY ORGANS - 49 6 



M.C. i. Sensation in Insects - - 496 



2. Organs of Vision - 5 O1 



3. The Median Ocelli, Stemmata, or Simple Eyes - 510 



n. The Stemmata of the Blow-Fly - 510 



b. Morphology and Comparative Anatomy of Simple 



Eyes in Arthropods 512 



SEC. 4. General Remarks on the Compound Eye - 515 



5. The Compound Eye in the Blow-Fly - - 526 



u. Structure of the Dioptron - - 526 



b. The Retina and Optic Nerve - 533 



SEC. 6. The Development of the Compound Eye - 538 



a. In the Arthropoda generally - 538 



b. The Development of the Compound Eye in the 



Blow-Fly - 545 



SEC. 7. The Theory of Arthropod Vision - 554 



,, 8. Further Remarks on the Optical Properties of the 



Compound Eye - 572 



n. On the Optical Properties of Refractive Cylinders, 



and the probable Relation of the several Types of 



Compound Eye in the Arthropoda - 572 



/'. On the Illumination of the Retinal End Organs under 



the Dioptric and Mosaic Theories of Vision - 575 

 i. Accessory Optic Phenomena in the Compound Eye 577 

 <f. Optical Constants of the Compound Eye of the 



Blow-Fly - - 581 



