PLATE LXXXIII. 
el. Cardinal sear. s. Median septum. 
F’. Cast of foraminal tube. y. Visceral area. 
h. Central muscle scar. vs. Vascular sinuses. 
j. Anterior lateral muscle scar. 
TREMATOBOLUS KEMPANUM (Matthew) (p. 619). 
Fiaure 1. Exterior of a ventral valve, showing elongate slit into which the foramen opens, drawn from a cast of a 
natural matrix. U.S. Nat. Mus. Cat. No. 52212a. 
la. A dorsal valve associated with the specimen represented by figure 1, drawn from‘ a cast of a natural matrix. 
U.S. Nat. Mus. Cat. No. 52212b. 
1b. A crushed ventral valve from Locality 308g, Middle Cambrian shales of Division 1b3 or 1b4 of Matthew’s 
section on Long Island [Matthew, 1898a, pp. 124 and 127], Kennebecasis Bay, St. John County, 
New Brunswick. University of Toronto, Canada. 
1c and 1d. Casts of the interiors of ventral valves. U.S. Nat. Mus. Cat. Nos. 52212c and 52212d, respectively. 
le. Cast showing cast of the foraminal tube; the dark portion represents the thickness of the shell. U.S. 
Nat. Mus. Cat. No. 52212e. 
1f. Cast of the interior of a dorsal valve. U.S. Nat. Mus. Cat. No. 52212f. 
1g. Natural cast of the interior of a ventral valve. U.S. Nat. Mus. Cat. No. 52212¢. (See fig. 1j.) 
th. Fragment showing the thickened shell on the posterior portion of a shell associated with the specimen 
represented by figure 1b. University of Toronto, Canada. 
li. Cast of the interior of a ventral valve. U.S. Nat. Mus. Cat. No. 52212h. 
1j. Interior of a ventral valve drawn from a cast of the specimen represented by figure 1g. U.S. Nat. Mus. 
Cat. No. 522121. 
1k. Enlarged view of a cast of-the interior of a ventral valve. U.S. Nat. Mus. Cat. No. 52212]. 
11. Partly exfoliated dorsal valve. U.S. Nat. Mus. Cat. No. 52212k. ; 
Im. Cast of the interior of a dorsal valve. U.S. Nat. Mus. Cat. No. 52212 1. 
In. Interior of a broken ventral valve drawn from a cast of a natural mold. U.S. Nat. Mus. Cat. No. 52212m. 
lo. Fragment of the interior of a dorsal valve, showing the peculiar median septum. U.S. Nat. Mus. Cat. 
No. 52212n. 
i 
With the exception of figures 1b and 1h, all of the specimens represented are from Locality 2u, Middle Cambrian, 
lowest beds exposed on the south side of Long Island [Matthew, 1898a, pp. 124 and 127], Kennebecasis Bay, St. John 
County, New Brunswick. 
TREMATOBOLUS PRISTINUS (Matthew) (p. 621). 
(Pl. LX XXIV, fig. 6.] 
Fiaure 2. Exterior of a ventral valve from Locality 2i, Middle Cambrian sandstones of Division 1b3 of Matthew on 
Hanford Brook, St. John County, New Brunswick. U.S. Nat. Mus. Cat. No. 52218a. 
2a. Interior of a ventral valve associated with the specimen represented by figure 2. U.S. Nat. Mus. Cat. 
No. 522138b. 
2b. Interior of a ventral valve associated with the specimen represented by figure 2. U.S. Nat. Mus. Cat. 
No. 52213c. : 
2c. Natural cast of the interior of the ventral valve represented by figure 2b. U.S. Nat. Mus. Cat. No. 52213d. 
The specimens represented by figures 2b and 2c are counterparts; another specimen (Cat. No. 56955b, from Locality 
2h) was used in drawing both figures. 
Ficure 2d. Cast of the interior of a dorsal valve from Locality 2h, Middle Cambrian sandstones of Division 1b2 of 
Matthew on Hanford Brook, St. John County, New Brunswick. U.S. Nat. Mus. Cat. No. 56955a. 
2e. Exterior and side views of a dorsal valve from Locality 301, Middle Cambrian sandstones of Division 1b2 
of Matthew on Hanford Brook, St. John County, New Brunswick. Original in the collection of the 
University of Toronto, Canada; cast in the United States National Museum (Cat. No. 58308). 
2f. Cast of the interior and side view of dorsal valve associated with the specimen represented by figure 2e. 
University of Toronto, Canada. Type specimen, figured by Matthew [1895a, Pl. IV, fig. 1c] as Obolus 
pristinus. 
2e¢. Cast of the interior of a dorsal valve associated with the specimen represented by figure 2e. University 
of Toronto, Canada. : 
2h. Broken cast of interior of dorsal valve, with side outline, associated with the specimen represented by 
figure 2e. University of Toronto, Canada. os 
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