xxsvi 



THE ACTINI.E. 



portion of it subsided by slow and ira{ierceptible degrees. 

 As tracts of it gradually sunk below tbe surface of tlie 

 deep, tbe summits of mountaius and table-lands would 

 remain as islands of diflerent magnitude and elevalion, 

 fortaing arcbipelagos elongated in tbe direction of the 

 mountain cliains. Now the coralline wliich constructs 

 the exterior wall and njass of the reefs never builds 

 laterally, and cannot exist at a greater depth than 

 twenty-five or thirty fathoms. Hence if it began to 

 lay the foundation of its reef on the submerged flanks 

 of an island, it would be obliged to build its wall 

 upwards in proportion as the island sunk down, so that 

 at length a lagoon would be formed between it and the 

 land. As the subsidence continued the lagoon would 

 decrease, the island would diminish, and the base of 

 the coral reef would sink deeper and deeper, while the 

 animal would always keep its top just below the surface 

 of the ocean till at length the island would perfectly 

 disappear, and a perfect atoll be left. If the island 

 were mountainous, each peak would form a separate 

 island in the lagoon, and the encircled islands would 

 have different forms, which the reefs would follow 

 continuously." 



Between the two hypotheses we leave the reader to 

 choose. Probably both may be true, and certaijily 

 both are compatible with each other. 



SEA ANEMONES. 



Various species of Sea Anemones, and particularly 

 those which it is customary to keep in Aquaria, are 

 represented in our Illustration. Figs. 1, 2, and .S are 

 tlie Actinia sulcata, which some authorities will not 

 recognize as a separate species, but believe to be the 

 young of Actinia effmta (Linnseus). It is also cited as 

 a synonym of Antliea cereus, from Michael Drayton's 

 couplet in his " Polyolbion -." — 



" Antbea of the flowers, that hnth a general charge. 

 And Syrinx of the weeds, that grow upon tlie marge." 



Fig. 4 is the Phymactis Sancia: HclerKe, so named by 

 Milne-Edwards from one of its favourite habitats ; 

 Fig. 5, tbe Actinia Capensis of Lesson; Fig. 6, Actinia 

 Peruviana (Lesson): Fig. 7, Actinia Sanctis Calhrrina;; 

 Fig. 8, Actinia amethyntina (Quoy) ; and Fig. 9, 

 Comactis viridis (Milne- Edwards). 



The latter, or Green Actinia, is an exquisitely 

 beautiful creature ; the brilliancy of its hues and the 

 extraordinary gracefulness of its tentacular crown, 

 ■when fully expanded, render it peculiarly attractive. 

 Hundreds, says Professor Allmann, may often be seen 

 in a single pool, and few scenes can give greater delight 

 to the naturalist than that in wliich tliese little Zoophytes 

 figure, when they unfold their emerald and rosy crowns 

 amid the algaj, millepores, and feather}' corals, the 

 co-tenants of their rocky home. The Green Actinia 

 is much esteemed in Greece, Italy, and Piovence as 

 a table dainty. Other species, as Actinia dianthus, 

 Actinia crassicornis, and Actinia coriacea are spoken 

 of as savoury food. 



The first section of the Antiniau«e includes the genera 



Anemonia, Actinia, and Metridium. We proceed to 

 notice a few of tlie more remarkable species. 



Actinia viridis has very numerous tentacula (some- 

 times not less tlian two hundred), exceeding in length 

 the breadth of the body, of a beautiful brown or olive 

 green, with a shade of rose at the extremity. The 

 trunk is of a greyish green or brown ; the disc brown, 

 with greenish rays. This species abounds in the 

 Mediterranean and in the English Channel. When 

 adhering to the sides of a rock a little below the 

 surface of the water — a position in which it is often 

 found in the Mediterranean — the tentacles bang sus- 

 pended as if tbe animal lacked room to extend them 

 in their ladiate form ; but when swimming horizontally 

 in a trai qm'l sea, they are outstretched in all directions, 

 and kept in a state of continual agitation. Fully 

 expanded, they float and balance themselves in the 

 water, despite its incessant motion, and the anemone 

 sparkles in the emerald depths like a globe of fire. 

 When numbers of them are assembled, the spectacle is 

 at once strange and interesting, recalling to tlie 

 spectator's mind the beautiful description of Charles 

 Kingsley : — 



''Onward they came in their joy, and around them the lamps of 



the sea-nympiis. 

 Myriad fiery globes, swam panting and heaving; and rainbows, 

 Crimson and azure and emerald, were broken in star-sliowers, 



lighting 

 Far tlirougli the wine-dark depths of the crystal, the gardens of 



Nert-us, 

 Coral and sea-fan and tangle, tlie blooms and the palms of tlie 



ocean."' 



Actinia difinthus (known also by a variety of 

 confusing and perplexing synon3'ms) has a smooth 

 cylindrical body ; its disc is marked in the centre with 

 clavate radiating bands; the tentacula are numerous, 

 irregular, the outer of small dimensions, and the whole 

 forming an edge or fringe of thick filaments. It is the 

 character of this species to attach itself permanently 

 to rocks, shells, and other objects in deep water, or 

 below low water-mark, and it cannot be removed with- 

 ont organic injury to the base. When contracted, the 

 body presents a short, thick, sub-cylindrical foiTO about 

 three inches in length and one and a half in diameter, 

 or five inches if fully expanded. The skin is smooth, 

 and either of a flesh colour, uniform olive, or yellowish 

 creamy white. A ring of white bands radiating from 

 tbe mouth ornaments the centre of the disc, and is 

 intercrossed by the usual lamellse — the tentacula 

 originating from the colourless transparent interspaces. 

 The margin is encircled by a dense fringe of great 

 and sparkling brillianc}', composed of innumerable short 

 tentacula or filaments, forming a thick, furry border. 



The Actinia mesemhryanthemum of Johnston, the 

 Actinia equina of Lesson, known in France as the Cut 

 d'ane, is frequently met with in the Channel on rocks 

 lying between high and low water marks. Its favour- 

 ite localities are those which the recession of the tide 

 exposes to the air at regular intervals. Its body 

 measures from two to three inches in height, and from 

 one inch to one inch and a half in diameter ; hemi- 

 spherical in shape wlien contracted, but when dilated 

 reseinbling a bell pierced at the summit. The ten. 

 * Kingsley, Andromeda, and Other Poems. 



