PLATE XXXY. 
a. Central lateral space of area. p. Pedicle groove. 
a’. Outer lateral space of area. s. Median septum. 
f. Flexure line of area. v. Visceral cavity. 
h. Central muscle scar. vs. Main vascular sinus. 
j. Anterior lateral muscle scar. 
LINGULELLA cCOoLLictA (Matthew) (p. 486). 
Figure 1. Exterior of an imperfect ventral valve, the type specimen. University of Toronto, Canada. 
la. Partly exfoliated ventral valve, showing visceral area and vascular sinuses. University of Toronto, 
Canada. : 
1b. Crushed and broken cast of the interior of a ventral valve. University of Toronto, Canada. 
The specimens represented by figures 1, la—b are from Locality 138n’, Middle Cambrian sandy shales of Division 
E3e, Dugald Brook, Cape Breton, Nova Scotia. The figures are drawn from three of the specimens illustrated by Mat- 
thew [1899b, Pl. I, figs. 3a-e], but closer identification is impossible. 
Figure lc. Exterior of a dorsal valve broadened and distorted by compression. Locality 13m, Middle Cambrian 
sandstones of Division E3f, Gillis Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 51772a. 
1d. Imperfect cast of interior of a dorsal valve from Locality 13n’, Middle Cambrian sandy shales of 
Division E3e, Dugald Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 52453a, 
le. Imperfect cast of interior of a flattened dorsal valve from Locality 10p, Middle Cambrian sandy shales 
of Division E2b, Dugald Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 35294a. 
1f. Cast of the interior of a ventral valve associated with the shell represented in figure le. U.S. Nat. Mus. 
Cat. No. 35294b. 
2. Cast of interior of ventral valve from Locality 18m, Middle Cambrian sandstones of Division E3f, Gillis 
Brook, Cape Breton, Nova Scotia, showing area and position of vascular sinuses. U.S. Nat. Mus. 
Cat. No. 57084a. i ; 
2a. Exterior of a slightly distorted ventral valve associated with the specimen represented by figure 2. U.S. 
Nat. Mus. Cat. No. 57084b. 
2b. Broad ventral valve, doubtfully referred to this species, from Locality 10p, Middle Cambrian sandy shales. 
of Division E2b, Dugald Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 57083a. 
2c. Dorsal valve associated with the specimen represented by figure 2a. U.S. Nat. Mus. Cat. No. 57084c. 
2d. Interior of a dorsal valve associated with the specimen represented by figure 2a, showing a strong median 
ridge and the position of the central muscle scars. U.S. Nat. Mus. Cat. No. 57084d. 
Figures 2, 2a-d represent forms corresponding to those referred by Matthew [1903, pp. 114-115] to Leptobolus 
collicia collis. 
LINGULELLA CANIA (Walcott) (p. 484). 
Ficures 3 and 3b. Casts of the interior of ventral valves from Locality 3i, Middle Cambrian sandy shale on McLean 
Brook, 1.5 miles west of Marion Bridge, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. Nos. 5245la 
and 52451c, respectively. Figure 3 represents the type specimen. 
3a. Partly exfoliated ventral valve associated with the shells represented in figures 3 and 3b. U.S. Nat. 
Mus. Cat. No. 52451b. 
3c. Exterior of dorsal valve from Locality 10s, Middle Cambrian sandstone on McLean Brook, near Marion 
Bridge, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 35295a. 
3d. Cast of interior of dorsal valve associated with the specimens represented by figures 3 and 3b. U.S. Nat. 
Mus. Cat. No. 52451d. 
LINGULELLA FERRUGINEA Salter (p. 496). 
[Pl]. XXIX, figs. 1, la-w, 2, 2a-f; Pl. XXX, fig. 1; and Pl. XX XT, figs. 3, 3a-c.] 
Ficures 4 and 4a. Partly exfoliated ventral valves, showing cast of the area and pedicle furrow, from Locality 3h, 
Middle Cambrian arenaceous shales, McNeil Brook, 1.5 miles east of Marion Bridge, Cape Breton, 
Nova Scotia. U.S. Nat. Mus. Cat. Nos. 51758a and 51758b, respectively. 
4b. Dorsal valve associated with the ventral valves represented by figures 4 and 4a. U.S. Nat. Mus. Cat. 
No. 51758c. 
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