MARINE AQUARIA 



side, a furrow extending along each arm in which are the ambulacra or 

 tube-suckers by which the animal moves and seizes its prey. The folded 

 stomach is connected to the mouth and occupies the greater part of the 

 central space. The four species of the Middle Atlantic coast are: 



Asterias forbesii, (Stimp.), the most common Atlantic coast ray, has 

 a comparatively small body with five rather broad arms swollen at the 

 base and tapering to a blunt point. The upper surface is rough and cov- 

 ered with short spines which are larger at the edges of the rays. The 

 colors are variable, but usually red or reddish-brown, with bright-orange 

 plates in the younger and yellowish-red, brown and purple in the older 

 individuals. It grows from lo to i6 inches in diameter and is common 

 from Massachusetts to Florida. Another form, A. vulgaris, has a very 

 similar body, but the five rays are not as swollen, a little more slender, 

 and taper to sharper points. It may also usually be distinguished by the 

 difference in color, as it is darker and the yellowish-red tones are absent. 

 Common and often associated with the above from Cape Cod to New 

 Jersey. Both are very destructive to oysters. 



Luidia clathrata, (Stimp.), is a slender five-rayed 4 to 5 inches in 

 diameter light colored ray, with the long arms tapering to a point and 

 fringed on the edges with distinct spines, but rather smooth on the surface. 

 The body is small and there are two rows of ambulacra. It has the habit 

 of breaking into pieces when taken from the water and can rarely be trans- 

 ported entire to the aquarium. Common from New York, to the Carolinas. 

 There are two other Florida forms of the genus. 



Echinaster sentus, (Ver.), is heavier than the above with five broader 

 arms and a relatively larger body, and has the surface rough with spines. 

 It is purplish-red in color, 4 to 4^ inches in diameter, and has two rows 

 of ambulacra. Found near the shore from New Jersey to Florida. 



Only the five-rayed forms are common on our coast, those of ten 

 and more rays are deep-sea forms. Starfishes are voraceous and only very 

 small ones should be introduced into the aquarium with other weaker 

 animals or with molluscs. If kept by themselves any of the described 

 forms often survive for a long time, especially in large aquaria. 



Brittle-Stars. The Ophiurans or Brittle-stars have the long dis- 

 tinct and serpentine cylindrical arms attaches like appendages to a small, 

 round body. They have no tube-suckers, locomotion being by move- 

 ments of the arms. Three species are common on the Middle Atlantic 

 coast, but most of them are found in warmer southern and western waters. 



Ophiopholis aculeata, (Ver.), has the upper surface of the body covered 

 with variously arranged plates surmounted by small, short spines. The 

 five arms are long, slender and tapering, having transverse oval plates 



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