List of Illustrations 



PLATES 



FACING PAGE 



I. Starfishes and Ophiuran, Asterias forbesi, Henricia 



sanguinolenta, and Ophiura brevispina . . 13 



II. Skeleton of Starfish, Asterias forbesi ... 19 



III. Aboral surface of Starfish, Asterias forbesi 21 



IV. Oral surface of Starfish, Asterias forbesi 22 

 V. Anatomy of Starfish, Asterias vulgaris ... 25 



VI. Rate of growth of Starfish, Asterias forbesi 41 



VII. Variation, Asterias forbesi .... .43 



VIII. Asterias forbesi and Asterius vulgaris ... 60 



IX. Asterias vulgaris . . ... 61 



X. Asterias tenera .... 63 



XI. Henricia sanguinolenta ... 65 



XII. Variation, Ophiopholis aculeata 67 



XIII. Skeleton of Ophiuran, Ophiopholis aculeata . 68 



XIV. Skeleton of Ophiuran, Ophiura brevispina 71 

 XV. Ophiura brevispina 79 



XVI. Ophiopholis aculeata 80 



XVII. Amphipholis squamata 81 



XVIII. Amphioplus abditus .82 



XIX. Amphioplus abditus and Amphioplus macilentus 84 



XX. Sea-urchin, Arbacia punctuiata 85 



XXI. Skeleton of Sea-urchin, Strongylocentretus dro- 



bachiensis 87 



XXII. Anatomy of Sea-urchin, Arbacia punctuiata 89 



XXIII. Skeleton of Disk-urchin, Echinarachnius parma . 92 



XXIV. Anatomy of Disk-urchins, Mellita pentapora and 



Echinarachnius parma 95 



XXV. Arbacia punctuiata 107 



XXVI. Strongylocentrotus drobachiensis 108 



XXVII. Echinarachnius parma no 



XXVIII. Mellita pentapora 112 



XXIX. Holothurians, Synapta roseola, Synapta inhcerens, 



and Thyone briareus 114 



XXX. Anatomy of Holothurian, Thyone briareus . . 117 



XXXI. Thyone briareus 133 



XXXII. Cucumaria pulcherrima, Thyone unisemita, Thyone 



scabra, and Synapta inhcerens. . . .136 



