840 NATURAL HISTORY OF AQUATIC ANIMALS. 



times prepare an indelible marking-ink from these ' Sand Dollars,' by rubbing off the spines and 

 skin, and, .after pulverizing, making the mass into a thin paste with water. A number of fishes 

 have been found to swallow this unpromising creature for food, and the flounders consume large 

 numbers of them." ' 



THE STAR-FISHES ASTEKIAS VULGARIS, Stimpsou ; ASTEBIAS FORBESII, Verrill. 



Only two species of Star-fish merit our attention in this report, not from any good they perform, 

 out from their destructive attacks upon our oyster-beds, which they are said to damage to the 

 extent of perhaps two hundred thousand dollars annually. These two Star-fishes, called Asterias 

 vutgaris and Asterias Forbesii, are so closely related to one another and so similar in appearance 

 as to require considerable skill at times to point out their differences; but when living the Axtcrinn 

 Forbesii can generally be recognized by its bright orange madreporic plate on the upper side of the 

 body, the corresponding plate in A. vulgarw agreeing more closely in color with the surrounding 

 portions of its disk. The fishermen do not distinguish between the two species; to them they are 

 both alike, and both are designated under the common but descriptive terms of " Star-fish," u Five- 

 finger," " Sea Star," or simply " Star." 



The Star-fish, as its name implies, is a star-shaped animal, consisting of a central disk from 

 which radiate, in the case of the species now under discussion, five elongate arms, which are not 

 marked off or separated in any way from the disk, but exist merely as prolongations from it. The 

 upper and lower sides arc quite different from one another. " The upper side presents a rough 

 surface of a greenish, brownish, reddish-green, or purple hue, which when it is dried turns to a 

 yellowish -brown. This is the leathery membrane covering the skeleton of the animal, which con- 

 sists of small limestone plates, united together at their edges by a sort of cartilage. This forms 

 the framework of the arms and disk, and acts as a chain-armor, encircling and protecting all the 

 soft parts within. On the lower side of the Star-fish this framework terminates in two series of 

 larger plates. This armor is sufficiently flexible to allow the Star-fish to bend himself clumsily 

 over or around anything he is likely to wish to climb upon or grasp." The entire upper surface 

 is covered with many short spines, which are largest and thickest at the edges of the rays and 

 upon the plates bordering the lower sides of the rays. Around the base of each spine there is a 

 circle of curious little claw-like appendages called pedicellariai, which may serve to aid in clearing 

 the upper surface, but whose functions are not satisfactorily made out. Scattered between the 

 spines are little soft water tubes, and at one side of the disk on the back is a sieve-like arrange- 

 ment, called the madreporic plate, for the admission of water. 



The under side of the body is softer than the, upper and much lighter in color. The month is 

 in the center of the disk; it bears no teeth, but is surrounded by an elastic tube. Five furrows 

 run from the mouth down the center of each arm. They are filled with numerous extensible soft 

 tabes, terminating in a disk and arranged in four rows. These are the so-called feet of the Star- 

 fish, and by means of them it moves about. The majority of the Star fishes are bisexual, but in 

 the two species under discussion the sexes are distinct. 



Our common Star-fishes, and especially the Asterias vulgaris, attain a large size, specimens 

 often measuring fifteen inches across, and upwards, on the Maine and Massachusetts coasts. 

 From this extreme we find all the intermediate sizes down to the very smallest. They inhabit 

 various kinds of bottoms, from above low- water mark to twelve or fifteen fathoms and deeper, but 

 it is in shallow water that they do the most damage. They live on muddy, sandy, rocky, and shelly 

 bottoms, and even on the piles of wharves, and are most abundant where they can find the 



1 VBERILL: Vineyard Sound Report, pp. 362, 363, 1871-'72. 



