DESCRIPTION OF PLATE 16. 
Chuangia nais Walcott (p. 171). 
1. Dorsal view and side outline of a fragmentary specimen of the central parts of a cephalon. Natural 
size. From Locality C64, Upper Cambrian, Kiu-lung group, southwest of Yen-chuang, Shan- 
tung. U.S. Nat. Mus., Cat. No. 57608. 
Chuangia fragmenta Walcott (p. 171). 
2. Dorsal view and side outline of a fragmentary specimen of central parts of a cephalon, * 1.5. From 
Locality C61, Upper Cambrian, Kiu-lung group, southwest of Yen-chuang, Shan-tung. U.S. 
Nat. Mus., Cat. No. 57607. 
Menocephalus abderus (Walcott) (p. 173). 
3. Type specimen showing portions of central parts of cephalon; and side outline of same, X 2. From 
Locality C19, Middle Cambrian, Ch’ang-hia limestone, at Ch’ang-hia, Shan-tung. U. S. 
Nat. Mus., Cat. No. 58076. 
Menocephalus acanthus Walcott (p. 173). 
4. Type specimen, showing portions of central parts of cephalon; and side outline of same, X 3. From 
Locality C22, Middle Cambrian, Ch’ang-hia limestone, at Ch’ang-hia, Shan-tung. U. S. 
Nat. Mus., Cat. No. 58077. 
4a. Fragment showing form of palpebral lobe and postero-lateral glabellar lobes of a cephalon asso- 
ciated with the specimen represented byfig.4, X 4. (C22.) U.S.Nat.Mus., Cat. No. 58078. 
4). Associated pygidium, X 3. (C22.) U.S. Nat. Mus., Cat. No. 58079. 
Levisia adrastia (Walcott) (p. 177). 
5. Top and side views of type specimen, X 4. From Locality C30, Middle Cambrian, Ch’ang-hia 
limestone at Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 58084. 
5a. Associated fragment of a cephalon. (C30.) U.S. Nat. Mus., Cat. No. 58085. 
Menocephalus ? depressus Walcott (p. 176). 
6. Top and side views of type specimen, X 4. From Locality C56, Upper Cambrian, Ch’au-mi-tién 
formation west of Tsi-nan, Shan-tung. U.S. Nat. Mus., Cat. No. 58080. 
6a. Free cheek (X 2) associated with this species at Locality C49, Upper Cambrian, Ch’au-mi-tién 
limestone, west-southwest of Ch’au-mi-tién, Shan-tung. U.S. Nat. Mus., Cat. No. 58081. 
Menocephalus ? sp. undt. Walcott (p. 176). 
7. A small cephalon doubtfully referred to this genus, X 3. From Locality C10, Middle Cambrian, 
Kiu-lung group, southwest of Yen-chuang, Shan-tung. U.S. Nat. Mus., Cat. No. 58082. 
7a. Associated fragment of glabella and fixed cheeks, X 4. U.S. Nat. Mus., Cat. No. 58083. 
Menccephalus acidalia Walcott (p. 174). 
8. Type specimen showing portions of central parts of cephalon; and side outline of same, X 4. From 
Locality C30, Middle Cambrian, Ch’ang-hia limestone, at Ch’ang-hia, Shan-tung. U. S. 
Nat. Mus., Cat. No. 58086. 
8a. Associated free cheek, X 1.5. U.S. Nat. Mus., Cat. No. 58087. 
Menocephalus agave Walcott (p. 176). 
9g. Top and side views of type specimen, X 3. From Locality C30, Middle Cambrian, Ch’ang-hia 
limestone, at Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 58088. 
Menocephalus acerius Walcott (p. 174). 
10. Top and side views of type specimen, X 2. From Locality C18, Middle Cambrian, Ch’ang-hia 
limestone, east of Ch’ang-hia, Shan-tung. U.S. Nat. Mus., Cat. No. 58089. 
10d. Free cheek, X 2. Associated with fig. 10. This occurs on a piece of limestone beside the pygid- 
ium of Crepicephalus damia, plate 13, fig. 14. U.S. Nat. Mus., Cat. No. 58090. 
Menocephalus acis Walcott (p. 175). 
11. Top and side views of type specimen, X 4. From Locality C35, Middle Cambrian, Ch’ang-hia 
limestone, at Ch’au-mi-tién, Shan-tung. U.S. Nat. Mus., Cat. No. 58091. 
Menocephalus admeta Walcott (p. 175). 
12. Top and side views of a minute cephalon doubtfully referred to this genus, X 6. From Locality 
C22, Middle Cambrian, Ch’ang-hia limestone, at Ch’ang-hia, Shan-tung. U.S. Nat. Mus., 
Cat. No. 58092. 
Ptychaspis calchas Walcott (p. 183). 
13 (Natural size) and 13a (X 1.5). Fragmentary specimens of glabella and palpebral lobes. From 
Locality C41, Upper Cambrian, Ch’au-mi-tién limestone, southwest of Ch’au-mi-tién, Shan- 
tung. U.S. Nat. Mus., Cat. Nos. 58093 and 58094, respectively. 
Ptychaspis callisto Walcott (p. 183). 
14. Type specimen showing portions of central parts of cephalon; and side outline of same, X 1.5. 
From Locality C64, Upper Cambrian, Kiu-lung group, southwest of Yen-chuang, Shan-tung. 
U. S. Nat. Mus., Cat. No. 58095. 
14a. Associated free cheek, X 1.5. U.S. Nat. Mus., Cat. No. 58096. 
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