DESCRIPTION OF PLATE 3. 



Lingulella manchuriensis Walcott (p. 69). 



1. Summit view and side profile of a ventral valve, X 10. U. S. Nat. Mus., Cat. No. 57560. 



ia. Summit view and side profile of a ventral valve, X 10. From Locality 35 q. Middle Cambrian, 

 Fu-chou series, collected in a low bluff on the shore of Tschang-hsing-tau Island, east of 

 Niang-niang-kung, Liau-tung, Manchuria. U. S. Nat. Mus., Cat. No. 57750. 



ib. Summit view and side profile of an exfoliated dorsal valve, X 10. U. S. Nat. Mus., Cat. No. 57561 . 



ic. Summit view and side profile of partly exfoliated broad form of dorsal valves. U. S. Nat. Mus., 

 Cat. No. 57751. 



id. Summit view and side outline of a dorsal valve, exhibiting the outer surface of the shell, X 10. 

 U. S. Nat. Mus., Cat. No. 57752. 



le. Enlargement to 4 diameters of a number of valves of this species, flattened in a fine arenaceous shale. 

 U. S. Nat. Mus., Cat. No. 57753. 



The specimens represented by figs, i, ib-e are from Locality 35 p, Middle Cambrian, Fu-chou series, 



calcareous and finely arenaceous shales, Province of Liau-tung, Manchuria. 

 Lingulella (Lingulepis) eros (Walcott) (p. 70). 



2. Exterior of a broken ventral valve, X 8. From Locality 07, Middle Cambrian, Kiu-lung group, 



west of Yen-chuang, Shan-tung. U. S. Nat. Mus., Cat. No. 525270. 



2a. Exterior of an associated broken dorsal valve, X 8. U. S. Nat. Mus., Cat. No. 525276. 

 Dicellomus parvus Walcott (p. 71). 



3. Exterior of a ventral valve, X 10. U. S. Nat. Mus., Cat. No. 52523^ 



30, and 36. Interiors of dorsal valves, X 10. U. S. Nat. Mus., Cat. Nos. 525230 and 525236. 



3C. Exterior of a dorsal valve, X 10. U. S. Nat. Mus., Cat. No. 52523^. 



3d. Exterior of a young shell, X 10. U. S. Nat. Mus., Cat. No. 525236. 



All of the specimens illustrated are from Locality C 0, Middle Cambrian, Kiu-lung group, thin platy lime- 

 stone, southwest of Yen-chuang, Shan-tung. The specimen represented by fig. 30 is on a piece of 

 limestone with Drepanura premesnili Bergeron. 

 Obolella asiatica Walcott (p. 72). 



4. Exterior of a ventral valve, X 4. From Locality C 32, Lower Cambrian, drift bowlder, Southern 



Shan-si. U. S. Nat. Mus., Cat. No. 525250. 



40. Exterior of an associated dorsal valve, X 4. U. S. Nat. Mus., Cat. No. 525256. 

 Yorkia ? orientalis Walcott (p. 72). 



5. Summit and side views of a ventral valve, X 8. U. S. Nat. Mus., Cat. No. 52521. 

 50. Diagrammatic sketch of the minutely ornate exterior surface. 



From Locality C71, Middle Cambrian, Ki-chou formation, southwest of Tung-yii, Shan-si. 

 Acrothele matthewi eryx Walcott (p. 73). 



6. Summit and side views of a partly exfoliated ventral valve, X3- From Locality C 4, Middle Cambrian. 



Kiu-lung group, limestone nodules southwest of Yen-chuang, Shan-tung. U. S. Nat. Mus., 



Cat. No. 52520. 



60. Summit view and side outline of a ventral valve, X 8. U. S. Nat. Mus., Cat. No. 57754. 

 66. A large ventral valve compressed in fine arenaceous shale, X 2. U. S. Nat. Mus., Cat. No. 57755. 

 6c. A compressed and partly exfoliated ventral valve, showing faint radiating ridges, X 3. U. S. Nat. 



Mus., Cat. No. 57756. 

 6d. Enlargement to 6 diameters of the posterior portion of a ventral valve, showing apex and false area, 



X 6. U. S. Nat. Mus., Cat. No. 57757. 



6e. View of a large dorsal valve, X 2. U. S. Nat. Mus., Cat. No. 57758. 



6/. A large dorsal valve compressed in finely arenaceous shale, X 2. U. S. Nat. Mus., Cat. No. 57759. 

 6g. An exfoliated ventral valve, showing muscle scars and vascular markings, X 4. U.S. Nat. Mus., 



Cat. No. 57760. 

 6h. View of a small, partly exfoliated dorsal valve, showing cast of a portion of a median ridge and the 



pits adjoining it near the beak. U. S. Nat. Mus., Cat. No. 57761. 

 The specimens represented by figs. 60, 6c-e, and 6g-h are from the limestones of Locality 35 r. Middle 



Cambrian, Fu-chou series, Province of Liau-tung, Manchuria. 

 The specimens represented by figs. 66 and 6/ are from finely arenaceous buff-colored shale, Localities 



36 e and 36 g, Middle Cambrian, Fu-chou series, Province of Liau-tung, Manchuria. 

 Acrothele ? minuta Walcott (p. 74). 



7. Exterior of a dorsal valve, X 15. From Locality C6, Middle Cambrian, Kiu-lung group, thin platy 



limestone, southwest of Yen-chuang, Shan-tung. U. S. Nat. Mus., Cat. No. 52519. 

 Acrothele rara Walcott (p. 74). 



8. Interior of a ventral valve, X 6. From Locality C 57, Middle Cambrian, Kiu-lung group, limestone 



nodules, north of Sin-t'ai-hien, Shan-tung. U. S. Nat. Mus., Cat. No. 525180. 

 80. Interior of an associated dorsal valve, X 6. U. S. Nat. Mus., Cat. No. 525186. 

 Acrotreta lisani Walcott (p. 75). 



9. 90, and 96. Summit, back, and side views of ventral valve, X 15. From Locality 022, Middle Cam- 



brian, Ch'ang-hia limestone, at Ch'ang-hia, Shan-tung. U. S. Nat. Mus., Cat. No. 525050. 

 gc. Exterior of an associated dorsal valve, X 15. U. S. Nat. Mus., Cat. No. 525056. 

 Acrotreta venia Walcott (p. 77). 



jo. Summit, side, and back views of a ventral valve, X 8. U. S. Nat. Mus., Cat. No. 57763. 



100. Interior of a dorsal valve showing median ridge and posterior muscle-scars. U. S. Nat. Mus., Cat. 



No. 57565. 



106. Exterior of very perfect dorsal valve, X 8. U. S. Nat. Mus., Cat. No. 57564. 

 The specimens represented by figs. 10, ioa-6 are from the shaly limestones of Locality 35q, Middle 

 Cambrian, Fu-chou series in compact shaly limestone about 120 feet (36.5 m.) above Locality 35p 

 from which Lingulella manchuriensis comes. Province of Liau-tung, Manchuria. 



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