MARINE AQUARIA 



with flat granules, and fringed with thick obtuse spines. The under side 

 is covered with regular rows of quadrangular plates. The color is. vari- 

 able, usually variegated and spotted with purple. It is a large species, 

 about 1 8 inches in diameter, and may be found in shallow water along the 

 entire Northern Atlantic coast. 



Ophiothrix angulata, (Ver.), is a small Florida species, sometimes 

 found farther north. The body is covered with short rough spines, and 

 the five arms are narrow, tapering and beset with long spines serrated on 

 the edges and ends. The color may be pinkish-yellow or light-brown, 

 according to the bottom upon which it lives. 



Amphiura squamata, (Ver.), is a small 2 to 4 inch diameter animal. 

 The body is less than ^ diameter, and the five arms threadlike and al- 

 most smooth on their surface. This is a delicate species found from New 

 Jersey northward below low-water marks. 



Sea Urchins. These animals are closely related to the Starfishes, 

 the shell-like covering showing the lines of union of the rays. They are 

 mostly deep-water forms, the two shallow-water species on the Middle 

 Atlantic States coast are: 



Arbacia punctulata, (Ver.), having a one inch in diameter shell with 

 j4 t-o % inch long spines. The color varies from straw-yellow and white- 

 ish-grey to brown, with the spines tipped with brown. A small species 

 found in shallow water from Massachusetts to Florida. 



Strongylocentrorus drobachiensis, (Grey,) the Common Sea-egg, has a 

 2 inch in diameter shell, greatly resembling a large chestnut-burr, usually 

 of greenish-purple color. The body is circular and sometimes depressed, 

 and the tube-feet slender. It moves slowly and feeds on small algae, 

 oscillatoria, and decaying animal matter.- Common in shallow water along 

 both the Atlantic and Pacific coasts, most abundant on the coast of Maine. 



Both these forms are harmless and useful aquarium inmates. 



Sand Dollars or Shield Urchins. This urchin, of which the 

 circular disc forming the skeleton, is a common object on some beaches, 

 belongs to the genus Echinarachnius, of which one species occurs in 

 Middle Atlantic coast waters. 



Echinarachnius parma, (Stimp.) has a skeleton consisting of a flat disc 

 composed of calcareous matter and sand, often 4 to 5 inches in diameter, 

 which in life is covered by short silky spines. The animal is somewhat 

 like a jellyfish in general form, occurs in deeper water, and is very rarely 

 taken near the shore. 



Sea Cucumbers. These higher forms of Echinoderms are native to 

 warm waters, and but one species occurs on the Middle Atlantic coast. 



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