PLATE XLIV. 
a. Central lateral space of area. p. Pedicle groove. 
h. Central muscle scar. ; y. Visceral cavity. 
LINGULELLA (LINGULEPIS) GREGWA (Matthew) (p. 554). 
Ficure 1. Very perfect ventral valve preserving the entire exterior surface, from Locality 10p”, Middle Caribrian 
sandstones between Indian River and McPhees Brook, Canes Breton, Nova Scotia. U.S. Nat. Mus. 
Cat. No. 51875a. 
Ja. Cast of the interior of a ventral valve from Locality 10p, Middle Cambrian sandstones of Division E2b, 
Dugald Brook, Cape Breton, Nova Scotia, showing the vascular sinuses. U.S. Nat. Mus. Cat. No. 
51873a. 
1b. Enlargement of a small ventral valve associated with the shell represented by figure la. U.S. Nat. Mus. 
Cat. No. 51873b. 
lc. Elongate ventral valve from Locality 10p’, Middle Cambrian sandstones on Gregwa Brook, Cape Breton, 
Nova Scotia. U.S. Nat. Mus. Cat. No. 51874a. 
1d. Partly exfoliated ventral valve associated with the shell represented by figure la. U.S. Nat. Mus. 
Cat. No. 51873c. 
le. Small ventral valve associated with the shell represented by figure 1c, showing the cast of a long pedicle 
furrow and a portion of the area. U.S. Nat. Mus. Cat. No. 51874b. 
1f. Cast of the interior of a very broad ventral valve associated with the shell represented by figure 1, on which 
a portion of the outer shell is preserved. U.S. Nat. Mus. Cat. No. 51875b. 
ig. Fragment of small ventral valve associated with the shell represented by figure 1, showing the area and 
the character of the outer surface of the shell. U.S. Nat. Mus. Cat. No. 51875c. 
th. Cast of part of the interior of a small dorsal valve associated with the specimen represented by figure la. 
U.S. Nat. Mus. Cat. No. 51878e. 
li. Small oval dorsal valve associated with the specimen represented by figure la. U.S. Nat. Mus. Cat. 
No. 518738. 
1j. Transversely oval dorsal valve, preserving the outer surface, associated with the specimen represented 
by figure la. U.S. Nat. Mus. Cat. No.51873g. The outer surface of this shell is enlarged in figure 1p. 
1k. Cast of the interior of a subtriangular dorsal valve, showing the visceral area, associated with the shell 
represented by figure la. U.S. Nat. Mus. Cat. No. 51873h. 
11. Cast of the interior of an elongate dorsal valve associated with the shell represented by figure la. U.S. 
Nat. Mus. Cat. No. 51873d. 
1m. Cast of the interior of an elongate dorsal valve associated with the shell represented by figure le. U.S 
Nat. Mus. Cat. No. 51874c. 
In. Cast of the interior of a dorsal valve associated with the shell represented by figure Ic. U.S. Nat. Mus. 
Cat. No. 51874d. The concentric lines of tubercles have been drawn in from other specimens (Cat. 
Nos. 51873i and 51873j from Locality 10p). 
lo. Enlargement of a portion of surface of a very perfectly preserved dorsal salle 12 mm. in length from 
Locality 18t”, Middle Cambrian sandstones of Divisions Ele and Eld on Dugald Brook, Cape Breton, 
Nova Scotia. U.S. Nat. Mus. Cat. No. 56792a. 
lp. Enlargement of the surface of the dorsal valve represented in figure 1j to show the irregular, concentric, 
undulating ridges. U.S. Nat. Mus. Cat. No. 51873g. 
LINGULELLA, (LINGULEPIS) LONGINERVIS (Matthew) (p. 555). 
Figures 2 and 2a. Exteriors of two small ventral valves, with nearly straight cardinal margins. Locality 13p, Middle 
Cambrian sandstones 40 feet above Division E2a on Dugald Brook, Cape Breton, Nova Scotia. U.S 
Nat. Mus. Cat. Nos. 51872a and 51872b, respectively. ; 
2b. Partly exfoliated ventral valve, with incurved cardinal margins. Locality 18g, Middle Cambrian 
sandstones 10 feet above Division E2a, Dugald Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. 
Cat. No. 56977a. 
2c. Interior of a broken ventral valve, showing eineeral cavity, area of central muscle scars, ete. Locality 
13f, Middle Cambrian pandatones 20 feet above Division E2a, Dugald Brook, Cape Breton, Nova 
Scotia. U.S. Nat. Mus. Cat. No. 56974a. 
2d. Exterior of a dorsal valve from Locality 10p, Middle Cambrian sandstones of Division E2b, on Dugald 
Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 34764a. 
2e. Interior of a dorsal valve from Locality 3440, Middle Cambrian sandstones of Division E2b, on Dugald 
Brook, Cape Breton, Nova Scotia. University of Toronto, Canada. Specimen figured by Matthew 
[1903, Pl. VII, fig. 6f]. The two figures should be compared. 
2f and 2g. Casts of parts of interiors of dorsal valves, showing position of central scars. Locality 18d, Middle 
Cambrian sandstones between Divisions E2a and E2b, Dugald Brook, Cape Breton, Nova Scotia. 
U.S. Nat. Mus. Cat. Nos. 56976a and 56976b, respectively. 
