MARINE AQUARIA 
Cirolena concharum, (Lat.), having a rounded segmental body and 
seven pairs of short legs. It is found swimming in shallow water among 
plants from Cape Cod to South Carolina, and is rarely over 1% inch long. 
Four other smaller and larger Isopods need no further mention. All are 
of similar form and habits. 
Mottusca. Of the Marine Mollusca it is proposed to mention 
only a few of the shallow-water Middle Atlantic coast species most likely 
to be found by the collector, as there are so many hundreds of genera and 
thousands of species that space will permit of their being only superfi- 
cially treated. 
Univatves. The most common Limpets, Periwinkles and Whelks, 
are: 
Acnea testudinalis, (Miull.), or Smooth Limpet, which has a thin, ele- 
vated, oblong-oval, saucer-shaped shell, with the apex turned forward. 
The surface is checked with minute radiating lines and the color is gener- 
ally a greenish-white, with darker brown stripes. It is about 5 inch long, % 
inch broad, and %4 inch high. The most common limpet, found along 
almost the entire Northeastern Atlantic coast. 
Crepidula fornicata, (Lam.), or Slipper Limpet, Quarter Deck, has a 
basin-shaped obliquely-oval shell, one side more oblique than the other, 
with a thin, shelf-like projection at the apical end, and the apex turned to 
one side. The surface is wrinkled with lines of growth, the aperture ob- 
liquely sub-oval, the edge entire and sharply defined with dark spots and 
blotches. Length 1% inches, breadth 1; inches, color light-brown. Found 
adhering to each other and to shells on the Atlantic coast generally. 
Littorina irrorata, (Say), or Common Periwinkle, has a thick varie- 
gated greenish shell of six whorls, a shallow suture, pointed apex and sub- 
oval aperture. Found in estuaries of the Middle and Southern States 
coast. 
Natica duplicata, (Say), or Coned Natica, has a large, dark and solid 1% 
to 2 inches shell, the upper whorls compressed to give a pyramidal form. 
The surface is marked with faint revolving lines, and the color is chestnut- 
brown or black. Found on sandy and muddy shores and beaches along 
the Northern Atlantic coast to Massachusetts. 
Columbella lunata, (Sowb.), or Dove Shell, has a small, ovate-conic, 
six-whorled, reddish-brown shell with flat whorls, a shallow suture and 
smooth surface. Crescent-shaped yellowish-white spots mark the surface, 
and the interior is a soft dove-color. Length § inch. Abundant from 
Cape Cod to Florida. 
Nassa obsoleta, (Say), or Small Whelk, has an ovular dark red- 
dish-brown or olivate, six-whorled, polished 1 inch long shell with some- 
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