FIGURE 
FIGURE 
PLATE LVI. 
el. Cardinal scars. s. Median septum. 
F’. Cast of foraminal tube. v. Visceral area. 
fa. False area. vs. Vascular sinuses. 
j. Anterior lateral muscle scar. x’. Cast of visceral cavity. 
ACROTHELE CORIACEA Linnarsson (p. 642). 
1. Top and back view of ventral valve from Locality 334f, Middle Cambrian limestone on Bornholm Island, 
Denmark. U.S. Nat. Mus. Cat. No. 51988a. 
la. Interior of a ventral valve from Locality 320f, Middle Cambrian limestone at Andrarum, Province of 
Christianstad, Sweden, U.S. Nat. Mus. Cat. No. 18208a. 
lb. Cast of interior of a ventral valve associated with the specimen represented by figure la. U.S. Nat. 
Mus. Cat. No. 18208b. 
le. Cast of interior of a ventral valve associated with the specimen represented by figure la. U.S. Nat. 
Mus. Cat. No. 18208e. : 
1d and le. Interiors of dorsal valves associated with the specimen represented by figure la. U.S. Nat. Mus. 
Cat. Nos. 18208e and 18208d, respectively. 
1f. Cast of interior of a dorsal valve associated with the specimen represented by figure la. U.S. Nat. Mus. 
Cat. No. 18208f. 
. Enlargement of the surface of a specimen associated with the shell represented by figure 1. U.S. Nat. 
Mus. Cat. No. 51983b. 
1h and 1h’. Top and side views of a.small ventral valve from Locality 8w, Middle Cambrian limestones at 
Andrarum, Province of Christianstad, Sweden, showing the small node on each side of the apex. 
U.S. Nat. Mus. Cat. No. 51978a. 
li. Top and back view of a very small ventral valve associated with the shell represented by figure 1h, showing 
a central posterior node, and a small node on each side of the apex. U.S. Nat. Mus. Cat. No. 51978b. 
1 
o 
.=) 
ACROTHELE (REDLICHELLA) GRANULATA (Linnarsson) (p. 663). 
2. Top and side views of exterior of a ventral valve from Locality 8z, Middle Cambrian limestones of the 
Paradoxides elandicus zone at Borgholm, Oeland Island, Sweden. U.S. Nat. Mus. Cat. No. 51991a. 
2a. Interior of a ventral valve from Locality 3100, Middle Cambrian limestones of the Paradowides tessini zone 
at Borgholm, Oeland Island, Sweden. U.S. Nat. Mus. Cat. No. 566438a. 
2b. Cast of the interior of a ventral valve from Locality 309f, Middle Cambrian shale at Borgholm, Oeland 
Island, Sweden. U.S. Nat. Mus. Cat. No. 23897a. 
2c. Interior of a ventral valve associated with the shell represented by figure 2, showing visceral area. U.S. 
Nat. Mus. Cat. No. 51991b. 
2d. Top and side views of exterior of a dorsal valve associated with the shell represented by figure 2. U.S. 
Nat. Mus. Cat. No. 51991c. 
2e. Interior of a dorsal valve associated with the shell represented by figure 2. U.S. Nat. Mus. Cat. No. 
51991d. : 
2f. Exterior of a dorsal valve associated with the shell represented by figure 2b, showing elongate tubercles 
at the apex. U.S. Nat. Mus. Cat. No. 23897b. 
2a, Enlargement of the surface of the specimen represented by figure 2. U.S. Nat. Mus. Cat. No. 23897b. 
2h. Exterior of a dorsal valve from Locality 320b, Middle Cambrian limestones at Gudhem, Province of 
Skaraborg, Sweden. U.S. Nat. Mus. Cat. No. 51992a. 
2i, Cast of an interior of a ventral valve associated with the dorsal valve represented by figure 2h, showing 
the cast of the visceral area (v), the expanded interior opening of the foraminal tube (F’), and main 
vascular sinuses (vs). U.S. Nat. Mus. Cat. No. 51992b. 
2}. Partly exfoliated ventral valve from Locality 309f, Middle Cambrian shale at Borgholm, Oeland Island, 
Sweden, showing the main vascular sinuses and branches. U.S. Nat. Mus. Cat. No. 23897c. 
2k. Fragment of the interior of a ventral valve associated with the shells represented by figures 2h and 2i, 
ereatly enlarged so as to show the outline of the visceral area. U.S. Nat. Mus. Cat. No. 51992c. 
184 
