DESCRIPTION OF PLATE 5—Continued. 
Pelagiella clytia (Walcott) (p. 89). 
14. View of the outer whorl of the type specimen of the species, X 10. U.S. Nat. Mus., Cat. No. 57786. 
From Locality C47, Upper Cambrian, Ch’au-mi-tién limestone at Ch’au-mi-tién, Shan-si. 
Helcionella rugosa orientalis (Walcott) (p. 91). 
15. Side view of a rather strongly curved specimen, X 10. From Locality C18, Middle Cambrian, 
Ch’ang-hia limestone, east of Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 57775. 
15a. Side view of a slender, banded specimen, X 10. From Locality C21, Middle Cambrian, Ch’ang- 
hia formation at Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 57776. 
Hyolithes cybele Walcott [see plate 6, fig. 7] (p. 92). 
16 (X 3) and 160 (X 2). Ventral and dorsal views of typical specimens of the species from Locality 
C2, Middle Cambrian, Kiu-lung group, south of Yen-chuang, Shan-tung. U.S. Nat. Mus., 
Cat. Nos. 57787 and 57788. 
16a. Ventral view of a specimen (X 4) from Locality C22, Middle Cambrian, Ch’ang-hia limestone, 
Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 57789. 
16c. Exterior and end views of operculum associated with this species in Liau-tung, X 4. From 
Locality 35n, Middle Cambrian, Fu-chéu series, Manchuria. U.S. Nat. Mus., Cat. No. 57790. 
Hyolithes daphnis Walcott (p. 93). 
17. Dorsal view of the type specimen, with outline of cross-section. Natural size. From Locality 
C64, Upper Cambrian, Kiu-lung group, 2.7 miles (4.3 km.) southwest of Yen-chuang, Shan- 
tung. U.S. Nat. Mus., Cat. No. 57797. 
Hyolithes delia Walcott (p. 94). 
18. Dorsal view of the type specimen of the species, X 6. From Locality C3, Lower Cambrian, Man-t’o 
shales, southwest of Yen-chuang, Shan-tung. U.S. Nat. Mus., Cat. No. 57798. 
Hyolithes sp. undt. Walcott (p. 94). 
19. Fragment of a species of Hyolithes, with a subtriangular aperture, associated with Orthotheca doris, 
X 6. From Locality C32, Lower Cambrian, drift bowlder, Southern Shan-si. U.S. Nat. 
Mus., Cat. No. 57796. 
Hyolithes sp. undt. Walcott (Operculum) (p. 94). 
20. Operculum associated with Hyolithes cybele, X 6. From Locality C4, Middle Cambrian, Kiu-lung 
group, limestone in shale, southwest of Yen-chuang, Shan-tung. U.S. Nat. Mus., Cat. No. 
57795. 
Orthotheca cyrene Walcott (p. 94). 
21. Ventral view and transverse section of a typical form of this species, X 4. U.S. Nat. Mus., Cat. 
No. 57799. 
21a. Dorsal view of a specimen showing the broad groove on the dorsal face, X 4. U.S. Nat. Mus., 
Cat. No. 57800. 
Figures 21 and 21a are drawn from specimens found at Locality C47, Upper Cambrian, Ch’au-mi-tién 
limestone, Ch’au-mi-tién, Shan-tung. 
Orthotheca cyrene dryas Walcott (p. 95). 
22, 221, and 22c. Dorsal and side views and outline of section, X 7. U.S. Nat. Mus., Cat. No. 57803. 
22a. Dorsal view, X 5. U.S. Nat. Mus., Cat. No. 57804. 
22b. Dorsal view (X 3) of specimen. U.S. Nat. Mus., Cat. No. 57805. 
All of the specimens illustrated are from Locality C2, Middle Cambrian, Kiu-lung group, 2 miles 
(3.2 km.) south of Yen-chuang, Shan-tung. 
Orthotheca glabra Walcott [see plate 6, fig. 7] (p. 97). 
23. A partly exfoliated specimen (X 8) from Locality C71, Middle Cambrian, Ki-ch6éu formation 
from 4 miles (6.4 km.) south-southwest of Tung-yii, Shan-si. U.S. Nat. Mus., Cat. No. 57566. 
23a. A minute, slender, broken specimen (X 8) from Locality C72, Middle Cambrian, Ki-chéu forma- 
tion 4 miles (6.4 km.) east of Fang-lan-chén, Shan-si. U.S. Nat. Mus., Cat. No. 57567. 
Orthotheca daulis Walcott (p. 95). 
24. Ventral view of the type specimen, X 2.5. From Locality C23, Middle Cambrian, Ch’ang-hia 
formation, east-southeast of Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 57809. 
24a. Transverse section of specimen associated with the specimen represented in fig. 24. U.S. Nat. 
Mus., Cat. No. 57810. 
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