There should certainly be a specimen of the Hermit Crab in a Whelk-shell; and the Cleanser Crab, Portunus depurator, has been tried, but these active and greedy Sea-Spiders must be closely looked after.
It remains to speak of the Star-Fish tribe, which affords some of the most beautiful and easily managed subjects for the Aquarium.
In the centre of the lower part of [Plate VI.] are a large and a small specimen of the beautiful scarlet species, Geniaster equestres; just above, to the right, the graceful pink Cribella oculata; further to the right, Asteria gibbosa; and immediately above the Cribella, the thin, leathery species, the bird’s foot Sea-Star, Palmipes membranaceus. All these species are small, easily managed, and especially suited to the Aquarium; as is also the finely-marked and long-rayed Ophicoma rosula, his deep scarlet, with bright black marks, and his slender limbs or rays, rendering him a conspicuous object. These Star-Fish glide round the Aquarium, by the aid of their thousand sucker-like feet, in a very interesting manner.
All the true Star-Fishes, the Asteriæ, have the body divided into rays, like a star, and are furnished with sucking feet, or cirrhi, which are tubular, and filled with water. The internal structure of these creatures is very intricate and beautiful, and the skeleton of almost any kind offers the appearance of that of some exquisitely symmetrical flower. There are fourteen British species of Star-Fish, the finest being the Sun-Star, Solaster papposa, the disk, surrounded with twelve or thirteen rays, varying in colour from scarlet to deep purple, the rays being sometimes of a different colour.
The Luidia fragilissima is also a large kind, sometimes two feet across, which is peculiar to the British shores. It possesses the peculiar faculty of breaking itself into fragments when enraged or captured; and, in a work by the lamented Professor Forbes, there is a very graphic and facetious account of a specimen that escaped him in a very determined way by a suicide of this kind.
Plate VI.
1. Edwardsia vestita.
2 & 3. Geniaster equestres.
4. Cribella oculata.