The last group of Worms here represented is that of the _Gephyrea_; with the advance of our knowledge it is probable that they will be found to be more intimately allied to the _Annulata_ than is now generally supposed; it will be seen indeed that _Echiurus_ has bristles at its hinder end; _Sipunculus_ is the best known representative of the unarmed _Gephyrea_; _Bonellia_ is interesting both from the fact that it owes its green colour to a matter closely resembling the chlorophyll of green plants, and from the possession by the female of a proboscis, which is protruded from the hole in the rock occupied by the worm: the male is very much smaller than the female, and is not nearly so well developed. Owing to the mode of lighting the Gallery, the visitor may have to shift his position several times before gaining a good view of the whole length of the proboscis. INDEX. Acanthaster, 114 Acanthobdella, 124 Acanthocephali, 122 Acmæidæ, 9 Actinometra, 113 Adeonidæ, 66 Ætheriidæ, 39 Alcyonidium, 67 Amaroucium, 99 Amathia, 67, 68 Amphineura, 7–9 Ampullariidæ, 14 Ancylus, 27 Annulata, 122 Anodonta, 39 Antedon, 111–113 Aphrodite, 122 Aplacophora, 9 Aplysiidæ, 23 Apoda, 115 Appendiculariidæ, 105 “Apple-Snails”, 14 Architeuthis, 48 Argonauta, 46 Ascaris, 120 Ascidia, 83, 93 Ascidiacea, 90 Ascidiæ Compositæ, 96 Ascidiæ Salpiformes, 99 Ascidiæ Simplices, 90 Ascopodaria, 73 Astartidæ, 38 Asterias, 108, 114 Asterina, 111 Asteroidea, 112, 113 Astrophyton, 114 Atlantidæ, 22 Auger-shells, 21 Auriculidæ, 26 Aviculidæ, 33 Bartlettia, 39 Basket-fish, 114 Basommatophora, 26 Bêche-de-mer, 115 Bipalium, 118 Bird’s head Coralline, 58 Bladder-worm, 117 Blastoidea, 112 Bloodworm, 124 Boat-shells, 20 Boltenia, 91, 92 Bonellia, 126 Borer, 43 Botryllidæ, 96, 97 Botrylloides, 97 Botryllus, 97, 98 Bowerbankia, 67 Brachiopoda, 74–82 Brechites, 44 Bristle-jawed worms, 122 Brittle Stars, 114 Bubble-shells, 23 Buccinidæ, 18, 19 Bugula, 58, 59 Bullidæ, 23 Caberia, 62 Calamaries, 4 Calyptræidæ, 14 Cardiidæ, 40 Carditidæ, 38 Carinariidæ, 22 Carinella, 118 Carrier-shells, 17 Cassididæ, 18, 19 Catenicellidæ, 66 Cavolina, 23 Cellularina, 58 Cephalopoda, 45–50 Cerithiidæ, 17 Cestoda, 116 Cestode parasites, 116 Chætoderma, 9 Chætognatha, 122 Chætopoda, 116, 122 Chama, 41 Chelyosoma, 93 Chilostomata, 57 Chirodota, 115 Chiroteuthis, 47 Chitonidæ, 7, 8 Chloeia, 122 Clams, 41 Clavagellidæ, 44 Clavelina, 94, 95 Clavelinidæ, 94 Clione, 24 Coat-of-mail shells, 7 Cockle, 40 Colella, 97, 98 Comatulidæ, 111 Conchologists, 17 Conidæ, 21 Convoluta, 118 Coralliophilidæ, 20 Corbula, 42 Cowries, 14 Crania, 74, 80 Creeping Coralline, 60 Crepidula, 14 Crinoidea, 112 Crinoids, 109 Crisia, 69 Crisiidæ 69 Cristatella, 71, 72 Cryptochiton, 8