DESCRIPTION OF PLATE 24. 
Redlichia chinensis Walcott [sec plate 7, figs. 11, 11a—c] (p. 104). 
1. X 2. Nearly entire dorsal shield from near Yunnan-Fu, Yunnan, China. U.S. Nat. Mus., Cat. No 
58792. 
1a. X 2. Posterior portion of thorax and pygidium associated in the same bed with the specimen 
represented by fig. 1. U.S. Nat. Mus., Cat. No. 58793. 
In a letter received from Dr. H. Mansuy since the text of this memoir was put in type he states that 
he had found a specimen of Redlichia chinensis on which the posterior five segments of the thorax 
have a well-marked, strong median spine comparable to that upon the corresponding parts of 
Elliptocephala asaphoides Emmons.* 
Zacanthoides typicalis Walcott. 
2. X 1.5. Dorsal view of type specimen from Locality 31, Lower Cambrian, Pioche shale, Pioche, Lincoln 
County, Nevada. U.S. Nat. Mus., Cat. No. 15454. 
Zacanthoides idahoensis Walcott. 
3. X 1.5. Thoracic segment of Zacanthoides idahoensis Walcott witha long median spine. Locality 
55¢, Middle Cambrian, Spence shale, 5 miles (8km.) west-southwest of Liberty, Idaho. U.S. 
Nat. Mus., Cat. No. 53438. 
Protolenus elegans Matthew. 
4 and 4a. Cranidium, natural size and enlarged, X 2. U.S. Nat. Mus., Cat. No. 58794. 
5. Flattened cranidium, natural size. U.S. Nat. Mus., Cat. No. 58795. 
6. Free cheek associated with specimen represented by figs. 3 and 3a. U.S. Nat. Mus., Cat. No. 58796. 
7. Enlargement of frontal limb of cranidium, X 7, to show the irregular, radiating raised ridges. U.S. 
Nat. Mus., Cat. No. 58797. 
The specimens illustrated by figs.4 to7 are from the type locality of the genus (Middle Cambrian) on 
Hanford Brook, St. John County, New Brunswick. 

*Smithsonian Misc. Coll., vol. 53, No. 6, p. 269, pl. 24, figs. 1, 9. 
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