The toxological properties of the Actinia have been attributed to certain special cells full of liquid; but M. Hollard believes that these effects are neither constant enough nor sufficiently general to constitute the chief function of these organs, which are found in all the species and over their whole surface, external and internal. Though quite incapable of discerning their prey at a distance, the sea anemone seizes it with avidity when it comes to offer itself up a victim. If some adventurous little worm, or some young and sluggish crustacean, happens to ruffle the expanded involucrum of an actinia in its lazy progress through the water, the animal strikes it at once with its tentacles, and instinctively sweeps it into its open mouth. This habit may be observed in any aquarium, and is a favourite spectacle at the "Jardin d'Acclimatation" of Paris, at noon on Sunday and Wednesday, when the aquatic animals are fed. Small morsels of food are thrown into the water. Prawns, shrimps, and other crustaceans and zoophytes inhabiting this medium, chase the morsels as they sink to the bottom of the basin; but it is otherwise with the Actinia; the morsels glide downwards within the twentieth part of an inch of their crown without its presence being suspected. It requires the aid of a propitious wand, directed by the hand of the keeper, to guide the food right down on the animal. Then its arms or tentacles seize upon the prey, and its repast commences forthwith.
Plate V.—Sea Anemones.
1, 2, 3. A. sulcata. 4. Phymactis sanctæ Helenæ. 5. Actinia capensis.
6. A. Peruviana. 7. A. sanctæ Catherinæ. 8. A. amethystina.
9. Comactis viridis.
The Actinia are at once gluttonous and voracious. They seize their food with the help of the tentacula, and engulf in their stomach, as we have seen, substances of a volume and consistence which contrast strangely with their dimensions and softness. In less than an hour, M. Hollard observed that one of these creatures voided the shell of a mussel, and disposed of a crab all to its hardest parts; nor was it slow to reject these hard parts, by turning its stomach inside out, as one might turn out one's pocket, in order to empty it of its contents. We have seen in Dr. Johnston's account of A. crassicornis that when threatened with death by hunger, from having swallowed a shell which separated it into two halves, at the end of eleven days it had opened a new mouth, provided with separate rows of tentacula. The accident which, in ordinary animals, would have left it to perish of hunger, became, in the sea anemone, the source of redoubled gastronomical enjoyment.
"The anemones," Frédol tells us, "are voracious, and full of energy; nothing escapes their gluttony; every creature which approaches them is seized, engulfed, and devoured. Nevertheless, with all the power of their mouth, their insatiable stomachs cannot retain the prey they have swallowed. In certain circumstances it contrives to escape, in others it is adroitly snatched away by some neighbouring marauder more cunning and more active than the anemone."
In Pl. IV. are represented the principal species of Anemone usually observed in the aquarium. Figs. 1, 2, and 3, A. sulcata, is surmised by Johnson to be the young of A. effœta (Linn.). It is also quoted as a synonyme of Anthea cereus, from Drayton's stanza:
"Anthea of the flowers, that hath a general charge,
And Syrinx of the weeds, that grow upon the marge."
Fig. 4, Phymactis Sanctæ Helenæ (Edw.); Fig. 5, A. Capensis (Lesson); Fig. 6, A. Peruviana (Lesson); Fig. 7, A. Sanctæ Catherinæ; Fig. 8, A. amethystina (Quoy); Fig. 9, Comactis viridis (Milne Edwards).