TABLE OF CONTENTS. ri 
REFERENCES TO THE PRINCIPAL FIGURES. 
For a comparison of the earliest stages of development, see the Segmentation of the Egg on 
* Plate I. figs. 1-4, for Comatula. 
Plate III. figs. 1, 26, Plate IV. figs. 1-7, for the Ophiuroidea (Amphiura and Ophiothrix). 
Plate V. figs. 6-11, Plate VII. figs. 1-12, for the Asteroidea (Asterina and Asteracanthion). 
Plate IX. figs. 1, 2, 17-20, Plate X. figs. 1-13, for the Echinoidea (Arbacia, Echinus, and Strongylocentrotus). 
Plate XIV. figs. 1-3, Plate XV. figs. 1 -3, for the Holothuroidea (Holothuria and Cucumaria). 
For the Formation of the Blastula and Gastrula, see 
Plate I. figs. 5, 11, 12, for Comatula. 
Plate III. figs. 3-7, Plate IV. figs. 8-10, for the Ophiuroidea (Amphiura and Ophiothrix). 
Plate V. figs. 12-25, Plate VII. figs. 12-20, for the Asteroidea (Asterina and Asteracanthion). 
Plate IX. figs. 3-12, 19-27, Plate X. figs. 14-24, for the Echinoidea (Arbacia, Echinus, Spatangus, Echinoear- 
dium, and Strongylocentrotus). 
Plate XIII. fig. 12, Plate XIV. figs. 3-5, Plate XV. figs. 3-6, for the Holothuroidea (Synapta, Holothuria, 
and Cucumaria). 
For the General Homologies of Echinoderm Larve, see 
Plate XV. figs. 14-27. 
For the Development of the different External Parts of the Pluteus or Larva, see 
Plate I. figs. 8, 9, 21, 27, 28, for Comatula. 
Plate III. figs. 9-14, 29, 30, Plate IV. figs. 11-19, for the Ophiuroidea. 
Plate V. figs. 1-3, 37-41, 44, 45, 47, 48, Plate VI. figs. 4, 12, 14, 16, 18, 24-31, 35-40, 44-46, Plate VII. 
figs. 19-34, for the Asteroidea (Asterina, Echinaster, and Asteracanthion). 
Plate IX. figs. 13-16, 30-35, 38-41, Plate X. figs. 26-37, Plate XI. figs. 1-17, 19-24, 28-20, for the Echinoidea 
(Arbacia, Strongylocentrotus, Echinus, Echinocyamus ? and Echinarachnius *). 
Plate XIII. figs. 1-8, 13-16, 18-27, 33-35, Plate XIV. figs. 4, 8, 9, 15-20, Plate XV. figs. 8-11, for the 
Holothuroidea (Synapta, Holothuria, and Cucumaria). 
For the Development of the Water System of the Vasoperitoneal Sacs, see 
Plate I. figs. 12-20, 22-24, for Comatula. 
Plate III. figs. 6-14, Plate IV. figs. 18-20, 27, 29, 31, for the Ophiuroidea (Amphiura and Ophiothrix). 
Plate V. figs. 20-28, 32-34, 36, 38, 43, 46, 49, Plate VI. figs. 2, 3, 6-9, Plate VII. figs. 20-34, Plate VIII. 
figs. 4-9, 11, 13, 14, 17, 18, for the Asteroidea (Asterina and Asteracanthion). 
Plate IX. figs. 5-13, 19, 21, 26, 27, Plate X. figs. 21-37, for the Echinoidea (Arbacia, Echinus, Spatangus, 
Echinocardium, and Strongylocentrotus). 
Plate XIII. figs. 4-37, Plate XIV. figs. 5-12, 17, 18, 21-27, Plate XV. figs. 6, 7, 9, for the Holothuroidea (Syn- 
apta, Holothuria, and Cucumaria). 
For the Development of the Young Echinoderm, see 
Plate I. figs. 24, 25, 29-36, Plate IT. figs. 1-23, for Comatula. 
Plate HI. figs. 14-20, 22-25, 29-33, Plate IV. figs. 20-34, for the Ophiuroidea (Amphiura and Ophiothrix). 
Plate V. figs. 3, 4, 29-31, 35, 37-41, 45, 47-49, Plate VI. figs. 1, 4, 5, 9, 11, 13, 17, 19, 90-22, 29-32, 37-42, 
47-51, Plate VIII. figs. 1-26, for the Asteroidea (Asterina, Echinaster, Pteraster, and Asteracanthion). 
Plate IX. figs. 35-37, 42-45, Plate X. figs. 37, 40-43, Plate XI. figs. 8, 17, 18, 25-27, Plate XII. figs. 30-34, 
for the Echinoidea (Arbacia, Strongylocentrotus, Echinus, Echinocyamus ? and Hemiaster). 
Plate XIII. figs. 6-11, 20-37, Plate XIV. figs. 17-27, Plate XV. figs. 8-11, for the Holothuroidea (Synapta, 
Holothuria, and Cucumaria). 
