PLATE LXI. 
cel. Cardinal sears. s. Median septum. 
F’. Cast of foraminal tube. vs. Vascular sinuses. 
fa. False area. 
ACROTHELE MATTHEW! (Hartt) (p. 647). 
Ficure 1. Ventral valve from Locality 301j, Middle Cambrian, St. John formation at Ratcliffs Millstream, St. John 
County, New Brunswick. Specimen figured by Walcott [1884a, Pl. I, fig. 4a], who states that it 
was labeled by Hartt as No. 342, Obolus (Discina) nitidus, nov. sp. 
Ja. Dorsal valve from Locality 301k, Middle Cambrian, St. John formation at St. John, New Brunswick. 
Type specimen, figured by Hartt [1868, fig. 221, p. 644], and by Walcott [1884a, Pl. I, fig. 4]. 
1b. Top and side views of an interior cast of a ventral eli e from Locality 3, Upper Cambrian limestones on 
Manuels Brook, Conception Bay, Newfoundland. U.S. Nat. Mus. Cat. No. 51994a. 
le. Cast of the interior of a compressed ventral valve associated with the shell represented by figure 1b, show- 
ing vascular canals. U.S. Nat. Mus. Cat. No. 51994b. 
1d. Interior of a ventral valve from Locality 6n, Middle Cambrian shales on Manuels Brook, Conception Bay, 
Newfoundland. U.S. Nat. Mus. Cat. No. 51996a. 
le. Exterior of a ventral valve from Locality 6g, Middle Cambrian limestone at CEOS Arm Harbor, Trinity 
Bay, Newfoundland. U.S. Nat. Mus. Cat. No. 51995a. 
1f. Interior of a dorsal valve associated with the shell represented by figure 1d. U.S. Nat. Mus. Cat. No. 
51996b. 
1g. Interior of a dorsal valve from Locality 301j, Middle Cambrian shales on Ratcliffs Millstream, St. John 
County, New Brunswick. U.S. Nat. Mus. Cat. No. 18170a. 
ACROTHELE MATTHEWI ERYX Walcott (p. 649). 
Figure 2. Top and side views of a partly exfoliated ventral valve, the type specimen, from Locality €4, Middle 
Cambrian limestone, Kiulung group, 3 miles southwest of Yenchuang, Sintai district, Shantung, 
China. U.S. Nat. Mus. Cat. No. 52520a. 
ACROTHELE MATTHEW! LATA Matthew (p. 649). 
Ficure 3. Interior of a crushed dorsal valve from Locality 301a, Middle Cambrian sandstones of Division 1b3 on Han- 
ford Brook, St. John County, New Brunswick. University of Toronto, Canada. Type specimen, 
figured by Matthew [1886, PI. V, figs. 17 and 17a] and by Hall and Clarke [1892c, P1. III, figs. 26-28]. 
ACROTHELE PRIMA CosTATA (Matthew) (p. 653). 
Fieure 4. Top view of a broken ventral valve with numerous cost, from Locality 2h, Middle Cambrian sandstones 
of Division 1b2 on Hanford Brook, St. John County, New Brunswick. U.S. Nat. Mus. Cat. No. 
52010a. 
4a. A crushed ventral valve with three coste, associated with the shell represented by figure 4. U.S. Nat. 
Mus. Cat. No. 52010b. 
4b. Interior of a broken dorsal valve associated with the shell represented by figure 4. U.S. Nat. Mus. Cat. 
No. 52010c. 
4c. Interior of a dorsal valve from Locality 6n, Middle Cambrian shales on Manuels Brook, Conception Bay, 
Newfoundland. U.S. Nat. Mus. Cat. No. 51984a. 
4d. Enlargement of the outer surface of a specimen associated with the shell represented by figure 4. U.S. 
Nat. Mus. Cat. No. 52010d. 
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