FIGURE 
PLATE XLV. 
ce. Trapezoidal area, including central, middle s. Median septum. 
lateral, and outside lateral muscle scars. v. Visceral cavity. 
h. Central muscle scars. vs. Main vascular sinus. 
j. Anterior lateral muscle scars. x. Heart-shaped cavity 
ps. Parietal band. 
LINGULELLA RADULA Matthew (p. 529). 
1. Imperfect cast of the interior of a ventral valve from Locality 301x, Upper Cambrian sandstones of Divi- 
sion 2c of Matthew’s section, Dunns Shore, Simonds, near St. John, New Brunswick. University 
of Toronto, Canada. 
la. Cast of an interior of a ventral valve from Locality 30ly, Upper Cambrian sandstones of Division 2c, 
east side of Courtney Bay, St. John, New Brunswick. University of Toronto, Canada. 
lb. Slightly distorted ventral valve from the same locality as specimen represented by figure la. University 
of Toronto, Canada. 
lec. Cast of the interior of a distorted ventral valve, associated with specimen represented by figure la. Uni- 
versity of Toronto, Canada. 
1d. Cast of the interior of a dorsal valve, the type specimen, showing central scars, etc., associated with the 
specimen represented by figure 1. University of Toronto, Canada. 
Figures 1, la-d, and lf are drawn from the specimens upon which Matthew based his figures [1891, Pl. XV, figs. 
7a-b and 8a-e], but closer identification is impossible. 
FIGURE 
le. Cast of the interior of a distorted ventral valve from the locality represented by figure la. Museum of 
Comparative Zoology, Cambridge, Massachusetts. 
lf. Cast showing part of the interior of a dorsal valve, associated with the specimens represented by figures 
la-c. University of Toronto, Canada. (See note following the description of figure 1d.) 
lg. Small ventral valve, preserving the exterior surface and convexity of outline in an unusually perfect 
manner. Locality same as specimen represented by figure la. Museum of Comparative Zoology, 
Cambridge, Massachusetts. (See note in description of figures 1k and 11.) 
lh. Interior of a ventral valve, preserving the form of the heart-shaped cavity as in Obolus. Locality same 
as specimen represented by figure la. Museum of Comparative Zoology, Cambridge, Massachusetts. 
li. Cast of the interior of a ventral valve, showing the visceral cavity and main vascular sinuses with unusual 
clearness. Locality same as specimen represented by figure la. Museum of Comparative Zoology, 
Cambridge, Massachusetts. 
1j. Cast of the interior of a dorsal valve, showing muscle scars, etc., beautifully preserved. Locality same as 
specimen represented by figure la. Museum of Comparative Zoology, Cambridge, Massachusetts. 
1k and 11. Interior of dorsal valve and cast of same. Locality same as specimen represented by figure la. 
Museum of Comparative Zoology, Cambridge, Massachusetts. It may be that the specimens repre- 
sented by figures lg, 1k, and 11 represent a small species distinct from Lingulella radula. All of the 
specimens are more or less distorted in the arenaceous shales in which they are embedded. 
LINGULELLA TRIPARILIS (Matthew) (p. 536). 
[Text figs. 44a-1, p. 537.] 
2. Broad form of ventral valve from Locality 13t’, Middle Cambrian sandstones of Division Elb on Dugald 
Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 57018a. 
2a and 2a’. Narrow form of ventral valve associated with the specimen represented by figure 2. U.S. Nat. 
Mus. Cat. No. 57013b. 
2b. Ventral valve on which a portion of the exterior surface of the shell is preserved. Associated with the 
specimen represented by figure 2. U.S. Nat. Mus. Cat. No. 57013c. 
2c. Cast of interior of a dorsal valve associated with the specimen represented by figure 2. U.S. Nat. Mus. 
Cat. No. 57018d. 
2d. Cast of interior of a dorsal valve from Locality 18t’’, Middle Cambrian sandstones of Divisions Elc and Eld, 
on Dugald Brook, Cape Breton, Nova Scotia. U.S. Nat. Mus. Cat. No. 57012a. 
2e. Narrow form of dorsal valve associated with the specimen represented by figure 2, preserving a portion 
of the outer shell, with side outline. U.S. Nat. Mus. Cat. No. 57013e. Another specimen (Cat. 
No. 51855a, from Locality 18t) was used in restoring certain portions of this figure. 
2f. Broad form of dorsal valve, associated with the specimen represented by figure 2. U.S. Nat. Mus. Cat- 
No. 570138. 
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