" On examining a living Asterias, the outer covering of its body is found to be composed of a dense coriaceous substance, in which numerous calcareous pieces are apparently imbedded. The cori aceous integument is generally colored externally with lively tints, and is evidently possessed of considerable irritability, as it readily shrinks under the knife, or upon the application of various stimuli. When cut into, it has a semi-cartilaginous hardness, and fibrous bands, almost resembling tendon in their aspect, may be seen to radiate from the centre of the body towards the ex tremities of the rays. There is no doubt that the movements of the rays are effected by the contractions of this fibrous membrane. The skeleton, or calcareous framework imbedded in the skin of the Asteridm, is by no means the least remarkable part of their structure. This consists of several hundred pieces, variously dis posed, and for the most part fitted togetherowith great accuracy; being either firmly soldered to each other, as we have seen them to be in the formation of the calcareous box that constitutes the central portion of Ophiurus, or united by ligaments, so as to allow of a considerable degree of motion to take place between them, as in the rays of Ophiurus, and other asteroid forms."— " The star-fishes, grossly considered, might be regarded as mere walking stomachs ; and the office assigned to them in the economy of nature, that of devouring all sorts of garbage and offal which would otherwise accumulate upon our shores. But their diet is by no means exclusively limited to such materials, since crusta ceans, shell-fish of various kinds, and even small fishes, easily fall victims to their voracity. Neither is the size of the prey upon which they feed so diminutive as we might suppose, from a mere inspection of the orifice representing the mouth ; for this is not only extremely dilatable, but, as we have found to be the case in the Actinide, the stomach is occasionally partially in verted, in order more completely to embrace substances about to be devoured: Shell-fishes are frequently swallowed whole, and a living specimen of Chama antiquata, Lin., has been taken from the digestive cavity of an Asterias, in an entire state. It appears, moreover, that it is not necessary for testaceous Mollusca to be absolutely swallowed, shell and all, to enable the Asteridm to ob tain possession of the inclosed animal, as they would seem to have the power of attacking large oysters, to which they are generally believed to be peculiarly destructive, and of eating them out of their shells. The ancients believed that, in order to accomplish this, the star-fish, on finding an oyster partially open, 'cunningly inserted one of its rays between the valves, and thus, gradually insinuating itself, destroyed its victim. Modern ob nervations do not, as far as we are aware, fully bear out the above opinion of our ancestors as to the mode in which star fishes attack oysters, although the destruction which they cause is pretty generally acknowledged.
" The observations recorded by 11T. Eudes Deslongchamps upon this subject are, however, exceedingly curious. As the waves had receded from the shore, so as to leave only one or two inches of water upon the sand, he saw numbers of Asterias rubens rolling in bunches, five or six being fastened together into a sort of ball by the interlacement of their rays. He ex amined a great number of such balls, and constantly found in the centre a Bivalve Mollusc, (Mactra Stultorum, Lin.) of an inch and a half in length. The valves were invariably opened to the extent of two or three lines, and the star-fishes were always ranged with their mouths in contact with the edges of the valves.
On detaching them from the shell which they thus imprisoned, he found that they had introduced between the valves large rounded vesicles with very thin walls, and filled with a transpa rent fluid. Each Asterias had five of these vesicles ranged around its mouth, but they were of very unequal size ; generally there were two larger than the rest, equal in size to large filberts, while the other three were not bigger than small peas. These vesicles appeared to be attached to the Asterias by short pellicles, and at the end of each was a round open aperture, through which the fluid contained in the vesicle flowed out drop by drop. No sooner was the animal detached from the shell that it was thus sucking, than the vessels collapsed, and became no longer distin guishable. The Mactra were all found to be more or less de voured, some having only their adductor muscles left; but, how ever little they had been injured, all had lost the power of closing their valves and were apparently dead ; nevertheless there was nothing to lead to the supposition that only dead shell fishes were attacked, so that it is difficult to imagine how the delicate vesi cles above described escaped injury from the closing of the valves. M. Deslongchamps thinks that probably the Asterias pours into the shell a torpifying secretion, and thus ensures the death of its victim." " The Asterias possesses no organs specially ap propriated to respiration ; but the sea water being freely admit ted into the general cavity of the body through a set of minute membranous tubes seen upon the exterior of the animal, bathes all the viscera, and consequently ensures a complete exposure of the circulating fluids to the influence of oxygen,—the whole peritoneal surface performing the office of a respiratory apparatus.
" The nervous apparatus of the Asteridaa, consists of a simple circular cord, which runs around the mouth of the animal; from this ring, three delicate filaments are given off opposite to each ray, one of which according to Tiedemann, runs along the centre of the ambulaceal grove upon the under surface of the body, and gives minute twigs to the locomotive suckers placed on each side of its course; the other two filaments, pass into the visceral cavity, and are probably distributed to the internal organs. There are no ganglia developed on any part of this nervous ap paratus ; or at least, if, as some writers assert, ganglionic en largements are visible at the points whence the radiating nerves are given off, they are so extremely minute as not in any degree to merit the appellation of nervous centres." " The general sense of touch in the Asteridm is extremely delicate, serving not only to enable them to seize and secure prey, but even to recog nise its presence at some little distance, and thus direct these animals to their food. Any person who has been in the habit of fishing with a line in the shallow bays frequented by star-fishes, and observed how frequently a bait is taken and devoured by them, will be disposed to admit this ; yet to what are we to at tribute this power of perceiving external objects ? It would seem most probably due to some modification of the general sensibility of the body, allowing of the perception of impressions in some degree allied to the sense of smell in higher animals, and related in the character to the kind of sensation by which we have already seen the Actinim and other polyps able to ap preciate the presence of light, although absolutely deprived of visual organs."