552 THE WHITE SAND-STAR. 
body from which it can hardly be expelled, the ambulacra, or feet, are seen to put themselves 
in motion, some being thrust out while others are being withdrawn. 
Our next examples are very curious species of Star-fish. 
The BritrLe-stars (Ophiocoma rosula), of which there are several species, are very appro- 
priately named, inasmuch as they are able to break up their rays in the most extraordinary 
manner, a capability which they mostly exercise when they feel alarmed. The generic name, 
Ophiocoma, is derived from two Greek words, the former signifying a serpent and the latter 
a lock of hair. 
The whole of the Brittle-stars are curious and restless beings. They can never remain in 
the same attitude for the tenth part of a second, but are continually twining their long arms, 
as if they were indeed the serpents with which Medusa’s head was surrounded. The least 
impurity in the water will cause these strange beings to break themselves to pieces in this 
extraordinary manner, but they never seem to disintegrate themselves with such rapidity as 
when they are touched, or otherwise alarmed. 
The lamented Professor Forbes has left an admirably quaint description of this suicidal 
process. Having in vain attempted to secure a perfect specimen of a Brittle-star, he thought 
that he might achieve that object by having a pail of fresh water lowered into the sea, so that 
as soon as the dredge reached the surface of the sea it might be transferred to the bucket of 
fresh water, and all the inmates killed at once by the shock. 
A fine specimen of the genus Luidia was then taken in the dredge. ‘‘As it does not 
generally break up before it is raised above the surface of the sea, cautiously and anxiously I 
sank my bucket toa level with the dredge’s mouth, and proceeded, in the most gentle manner, 
to introduce Luidia to the purer element. Whether the cold element was too much for him, 
or the sight of the bucket too terrific, I know not ; but ina moment he began to dissolve his 
corporation, and at every mesh of the dredge his fragments were seen escaping. In despair, I 
grasped the largest, and brought up the extremity of an arm with its terminating eye, the 
spinous eyelid of which opened and closed with something exceedingly like a wink of derision.” 
These Brittle-stars are, however, extremely capricious in their exercise of this curious 
power. It sometimes happens that, as in the instance so amusingly narrated, the creatures 
break themselves to pieces without any apparent provocation, while, in other cases, specimen 
after specimen may be taken, handled, killed, or wounded, without the loss of a ray. Even 
in the aquarium, they are equally uncertain in their habits, at one hour being entire and 
splendid specimens, and at the next being little but a solitary dise amid a ruined heap of 
broken arms. 
The Brittle-stars are abundant in the warmer waters. When Dr. Gould published his 
‘“‘ Report on Invertebrata of Massachusetts,’’ 1841, his enumeration of Hcehinodermata embraced 
Echinus granulatus, Sea-egg, Sea-urchin ; Asterias, four species, A. rwbens being the common 
Star-fish, or Five-finger ; and two species of Ophiura, which were visible only as brought up 
by dredging, or from the stomachs of fishes. The latter were not, as they are in the tropical 
waters, found crawling on the objects at low tide or in shallow waters. The coral shrubs, and 
dead and crumbling blocks of Meandrinas astreas, ete., are numerously inhabited by them. 
There are many others since discovered by the extensive dredging in deep and shallow waters 
on our coast, 
THE WHITE SAND-STAR (Ophiurus albidus). 
The word Ophiurus is of Greek origin, signifying snake-tail, and is therefore very appro- 
priately given to these curious beings, whose slender arms twist and coil just like a handful of 
small serpents. 
The Ophiuri are quite as voracious as the ordinary Star-fishes, and are able by means of 
the long arms to convey food to the mouth, which is placed in the central disc. The young of 
these Echinodermata are quite as curious as those of the sea-urchins, to which, indeed, they 
bear some resemblance. They have long been known to naturalists under the title of Easel 
animalcules, on account of their peculiar shape, their real origin not being suspected until later 
