PLATE XXXIV. 
LINGULELLA CONCINNA Matthew (p. 486). 
[Pl. XX XIU, figs. 2, 2a-h] 
Fiaure 1. This ventral valve is somewhat doubtfully referred to this species. The specimen from which the figure 
was drawn occurs in Locality 310h, Upper? Cambrian shales in the Province of Skane, Sweden, and 
is more nearly related to some forms of Lingulella concinna than to other species from the Upper 
Cambrian and Lower Ordovician. U.S. Nat. Mus. Cat. No. 14932a. 
Ja-h. Ventral valves illustrating variations in outline, convexity, etc., from Locality 3h, Upper Cambrian 
shale on McNeil Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. Nos. 51762a-h, respectively. 
li-q. Dorsal valves associated with the ventral valves represented by figures la-h. U.S. Nat. Mus. Cat. Nos. 
517621-q, respectively. 
lr. Three ventral valves and fragments of a dorsal valve associated with the shells represented by figures la-q 
(X 2). U.S. Nat. Mus. Cat. No. 51762r. 
OBOLUS SEPTALIS (Walcott) (p. 414). 
[Pl. XXIM, fig. 34] 
Figure 2. Exterior of dorsal valve. Collection of Mr. Byron E. Walker, Toronto, Canada. 
2a. Cast of interior of dorsal valve, the type specimen. U.S. Nat. Mus. Cat. No. 51612a. 
The specimens are both from Locality 14s, Middle Cambrian Ogygopsis zone on Mount Stephen, British Columbia. 
LINGULELLA (LINGULEPIS) ACUMINATA (Conrad) (p. 545). 
[Pl. XL, figs. 1, 1a-s; Pl. XL, figs. 1, la-n; and Pl. XLII, figs. 1, 1a-o.] 
Fiaure 3. Ventral valve with the apex worn off, from Locality 7z, Upper Cambrian limestone about 3 miles southeast 
of Emigrant Pass, Esmeralda County, Nevada. U.S. Nat. Mus. Cat. No. 51884a. 
3a. Ventral valve intermediate in form between specimens represented by figures 3 and 3b, from Locality 7y, 
Upper Cambrian limestones 2.5 miles southeast of Emigrant Pass, Esmeralda County, Nevada. U.S. 
Nat. Mus. Cat. No. 56967a. 
3b. Broad form of ventral valve with apex broken off, from Locality 7x, Upper Cambrian limestones 2.5 miles 
southeast of Emigrant Pass, Esmeralda County, Nevada. U.S. Nat. Mus. Cat. No. 56967b. 
3c and 3d. Dorsal valves associated with the shell represented by figure 3. U.S. Nat. Mus. Cat. Nos. 51884b 
and 51884c, respectively. 
3e. A small, slender ventral valve associated with the shell represented by figure 3. U.S. Nat. Mus. Cat. No. 
51884d. 
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