MARINE AQUARIA 
composed of sand and mud. Found in sand and gravel and under or 
attached to fixed objects; from Cape Cod to Maryland. 
Cistenides gouldu, color light red, body short and slightly curved, 
head obliquely flat, with two broad groups of golden bristles on each side 
of head, % to 2 inches long. Constructs conical horn-shaped tubes of a 
single layer of sand. Found on sandy beaches from New Jersey north- 
ward. 
Clymenella torquata, color pale red with bright bands, 4 inches long ; 
body segmented and bristled, head funnel-shaped. Constructs nearly 
straight tubes of sand. Ranges from New Jersey northward close to low- 
water marks. 
Serpular dianthus, color variable, dull olive and reddish, with plume- 
like gills which form a wreath about the head. ‘The white calcareous tube 
is 3 inches long and % inch in diameter, and has the end coiled and con- 
torted. The free end has acircular opening with an operculum. Found 
in tide-pools attached to shells and rocks, from Cape Cod to Florida. 
These are a few of the most characteristic forms. 
Mottuscorpa. Of the Polyzoa there are hundreds of named species, 
mostly consisting of colonies of small polyplike organisms, depositing 
calcareous matter and attached to plants, stones and other fixed objects. 
The Branchiopods are somewhat similar to the lamellibranch molluscs, 
but the two valves of the shell are always dissimilar. They are usually 
fastened to some marine object by a fleshy peduncle extending between or 
through the valve; and the body cavity is lined with cilia. In the order 
Inarticulata the hinge of the shell is wanting and the thin plates may be 
moved in every direction. Jn the order Articulata the valves are articu- 
lated by a hinge formed by teeth on the. lower and sockets on the upper 
valve. They are much lower forms than the Mollusca and need not be 
here further described. 
EcuHINODERMATA. These Radiates of the higher type have an ex- 
terior skeleton and most of them have the spines from which the name is 
derived. They include the Asteroidea or Starfishes, Ophiuroidea or 
Brittle-stars, Desmosticha or Sea-urchins, Holothuroidea or Sea-cucumbers, 
and the Crinoidea or Feather-stars and Stone-lilies. Brief mention of 
these will be made, description being confined to the most common species 
of the Middle Atlantic coast. 
Srar Fisues or Rays. These animals derive their name from their 
asteroid or starshaped forms, the different species having from § to 22 
rays. The external skeleton is complex, and consists of calcareous plates 
and spines either firmly united to form a solid shield or separate and im- 
bedded in the integument. The mouth is in the centre of the ventral 
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