320 



American Seashelh 



Figure 68. Common Eastern 



Chiton, Chaetopleiira apiculata 



Say, Yo inch. 



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 

 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. 



