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320 American Seashelh
areas with 15 to 20 longitudinal rows of raised, neat beads. Lateral areas
distinctly defined, raised and bear numerous, larger, more distantly spaced
beads which may or may not be present on
Figure 68. Common Eastern
Chiton, Chaetopleiira apiculata
Say, Yo inch.
the more dorsal region. Interior white or
grayish. Slits of anterior valve 11, central
or middle valves i , posterior valve 9 to 11.
Girdle narrow, mottled cream and brown,
microscopically granulose and with sparsely
scattered, transparent, short hairs. 22 to 24
gill lamellae in each gill which start just be-
hind the juncture of the head and foot and
extend all the way back to the posterior
margin of the mantle where there is located
a small, single-lobed lappet. Common from
I to 15 fathoms.
In the north, the exterior color is buff to ashen, rarely reddish. On the
west coast of Florida, where they are commonly found attached to Finna
shells, the colors vary from light-gray, mauve, yellow to white, and are
commonly with a darker or lighter streak down the center or rarely with
longitudinal blue stripes.
Genus Ischnochiton Gray 1847
Subgenus Stenoplax Carpenter 1878
Ischnochiton floridanus Pilsbry Florida Slender Chiton
Miami to Dry Tortugas, Florida.
I to 1 34 inches in length, about 3 times as long as wide, elevated, with
the valves roundly arched, not carinate. Color whitish to whitish green with
markings of olive, blackish olive or gray. Lateral axeas raised and with wavy,
longitudinal riblets which are commonly strongly beaded. Central areas
with wavy, longitudinal ribs. Interior of valves mixed with white, blue
and pink, rarely all pink or all white. End valves concentrically (or rarely
axially) beaded. Intermediate valves with i slit, posterior valve with 9.
Girdle marbled with bluish and gray, and densely covered with round, solid,
finely striated scales. Moderately common.
Ischnochiton purpmascens C. B. Adams (Purplish Slender Chiton)
from the West Indies is very similar, but the end valves and lateral areas
have smooth, instead of beaded, wavy, concentric riblets. Common.
Ischnochitoji papillosus C. B. Adams Mesh-pitted Chiton
Tampa to the Lower Keys and the West Indies.