PLATE XCVIII. 
OrvstIA LENTICULARIS (Wahlenberg) (p. 765). 
[Pl]. XCVII, figs. 6, 6a-c.] 
Fiaures 1; la, la’; and 1b. Exterior surface of ventral valves, illustrating variation in radial coste, with side outline 
of specimen represented by figure la. Locality 390n, Upper Cambrian limestone at Hunneberg, 
Province of Skaraborg, Sweden. U.S. Nat. Mus. Cat. Nos. 52400a-c, respectively. 
le and 1c’. Top and posterior views of ventral valve associated with the specimens represented by figures 
1, la-b. Figures 1c and 2b represent forms having the characters of Matthew’s ‘‘ Orusia lenticularis 
strophomenoides.”” U.S. Nat. Mus. Cat. No. 52400d. 
1d and 1d’. Top and side views of a smooth ventral valve associated with the specimens represented by 
figures 1, la-b. U.S. Nat. Mus. Cat. No. 52400e. 
Je and le’. Natural mold of the interior of ventral valve, with posterior outline. Locality 310a, Upper Cam- 
brian shales of Olenus truncatus zone on Oeland Island, Sweden. U.S. Nat. Mus. Cat. No. 52406a. 
lf, 11’, and 11”. Top, side, and posterior views of a very smooth ventral valve associated with the specimen 
represented by figure le. U.S. Nat. Mus. Cat. No. 52406b. 
lg and lg’. Top and side views ofa dorsal valve associated with the specimen represented by figure le. U.S. 
Nat. Mus. Cat. No. 52406c. 
th, 1i, 1j, 1k, 11, 1m, In, and lo. Series of dorsal valves and side outlines illustrating variation in form of 
shell and character of surface. Locality 390n, Upper Cambrian limestone at Hunneberg, Province 
of Skaraborg, Sweden. U.S. Nat. Mus. Cat. Nos. 52400fm, respectively. 
1p. Cast of the interior of a small ventral valve, showing the extension of the main vascular sinuses back 
across the umbonal cavity; also the division of the muscle area between them by a narrow septum. 
This specimen is in the tray with the specimens represented by figures le-g, but none of the speci- 
mens received locality numbers when they were first collected and the locality may be considered 
doubtful. U.S. Nat. Mus. Cat. No. 52406d. 
2and 2’. Top and side views of a ventral valve from Locality 3, Upper Cambrian limestone 300 feet above 
the Paradoxides zone on Manuels Brook, Conception Bay, Newfoundland. U.S. Nat. Mus. Cat. 
No. 52402a. 
\ 2a. Ventral valve, with numerous radiating cost, from Locality 6v, Upper Cambrian limestones 325 feet 
above the Middle Cambrian on Manuels Brook, Conception Bay, Newfoundland. U.S. Nat. Mus. 
Cat. No. 52404a. 
2b. A small, very convex, and rugose ventral valve in which the radiating costee are nearly obliterated, 
associated with the specimen represented by figure 2a. Figures Ie and 2b represent forms having 
the characters of Matthew’s ‘‘ Orusia lenticularis strophomenoides.’’ U.S. Nat. Mus. Cat. No. 52404b. 
2e and 2d. Compressed ventral valves associated with the specimen represented by figure 2. U. 8. Nat. 
Mus. Cat. Nos. 52402b and 52402c, respectively. 
2c’. Side outline of specimen represented by figure 2c. 
’ Qe, 2f, 2h, 2i, and 2j. Series of dorsal valves associated with the specimen represented by figure 2, illus- 
trating variation in form of shell and surface characters. U. 8. Nat. Mus. Cat. Nos. 52402d—h, 
respectively. ° 
2i’. Posterior view of specimen represented by figure 2f. 
. 2g. Dorsal valve associated with the specimen represented by figure 2a. U.S. Nat. Mus. Cat. No. 52404c. 
. 2k. Compressed ventral valve associated with the specimen represented by figure 2. U.S. Nat. Mus. Cat. 
No. 52402i. 
3. Enlargement of a fragment of shale on which the shells show a considerable variation. 
3a and 3b. Ventral and dorsal valves. 
The specimens represented by figures 3, 3a-b are in the collection of the University of Toronto, Canada, and are 
labeled as coming from St. John, New Brunswick. They are among the material used by Matthew in drawing figures 
9a-d of his paper [1892, Pl. XII], but closer identification is impossible. 
ORUSIA LENTICULARIS LYNCIOIDES (Matthew) (p. 769). 
Figure 4. Ventral valve from Locality 308b, Upper Cambrian limestone in shales of Division C3a of Matthew, Ger- 
maine Street, St. John, New Brunswick. University of Toronto, Canada. Type specimen figured 
by Matthew [1892, Pl. XII, fig. 10a]. 
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