 Fig. 143. Single spine of Star-fish, with surrounding appendages; magnified. |  Fig. 144. Limestone network of back of Star-fish. | |
 Fig. 145. Madreporic body of Star-fish; magnified. | ||
These animals have singular mode of eating; they place themselves over whatever they mean to feed upon, as a cockle-shell for instance, the back gradually rising as they arch themselves above it; they then turn the digestive sac or stomach inside out, so as to enclose their prey completely, and proceed leisurely to suck out the animal from its shell. Cutting open any one of the arms we may see the yellow folds of the stomach pouches which extend into each ray; within the arms, extending along either side of the upper surface, are also seen the ovaries, like clusters of small yellow berries. Immediately below these, along the centre of the lower floor of each ray, runs the ridge formed by the ambulacral furrow, and upon either side of this ridge are placed the vesicles, by means of which the tentacles may be filled and emptied at the will of the animal; the rest of the cavity of the ray is filled by the liver. The mouth, which is surrounded by a circular tube, is not furnished with teeth, as in the Sea-urchin; but the end of each ambulacral ridge is hard, thus serving the purpose of teeth.
Cribrella. (Cribrella oculata Forbes.)
Our coast, as we have said, is not rich in the variety of Star-fishes. We have two large species, one of a dark-brown color ([Fig. 132]), the Astracanthion berylinus, and the other, the A. pallidus, of a pinkish tint; then there is the small Cribrella, inferior in structural rank to the two above mentioned. ([Fig. 146.]) This pretty little Star-fish presents the greatest variety of colors; some are dyed in Tyrian purple, others have a paler shade of the same hue, some are vermilion, others a bright orange or yellow. A glass dish filled with Cribrellæ might vie with a tulip-bed in gayety and vividness of tints.
Fig. 146. Cribrella from above; natural size.