Page:Proceedings of the United States National Museum, Volume 76.djvu/144

	Plate 3		Page
Tuzoia burgessensis, new species			8
Fig.	1.	A large left valve. Keel pressed directly downward. Folding to accommodate this reduction in convexity resulted in a crowded zone about half way to the margins. Paratype, Cat. No. 80477, U.S.N.M. Middle Cambrian, Burgess shale; (loc. 35k), near Field, British Columbia.
Tuzoia manchuriensis, Resser and Endo MSS			9
	2.	Upper anterior quadrant of left valve. Note long extension of dorsal line and narrowed keel. Paratype, Cat. No. 80481, U.S.N.M.
	3.	Major portion of left valve. Reticulations on keel and general surface partially visible. Note worm borings. Holotype, Cat. No. 80482, U.S.N.M. Middle Cambrian, Matrix; soft yellow shale. Fig. 2, from Huo-lien-chai, and fig. 3, from Mount Tang-shih-ling, near Yen-tai, Manchuria.
	Plate 4
Protocaris pretiosa, new species			13
Fig.	1.	Abdominal portion of body and both valves of this interesting form. Right valve extended and practically undistorted. Left valve which rests at an oblique angle to the bedding plane crushed down and thereby extended rearward.
	2.	Counterpart of same specimen as figure 1, with shell removed to expose most of the body. Note the numerous segments and the bifurcated caudal extremity. Holotype, Cat. No. 80483, U.S.N.M. Middle Cambrian, Burgess shale; (loc. 35k) near Field, British Columbia.
Tuzoia retifera, Walcott			7
	3.	Major portion of a poorly preserved specimen referred to the species with some doubt, in which the two valves became flattened out on the same plane. In this case the original convexity of each valve was reduced by overthrust faulting along the keel, together with parallel folding in other areas thus almost effacing the reticulations. Plesiotype, Cat. No. 80484, U.S.N.M. Middle Cambrian, Burgess shale; (loc. 35k) near Field, British Columbia.
	Plate 5
Tuzoia polleni, new species			9
Fig.	1.	Large right valve in which the spines and reticulations are well preserved. Holotype, Cat. No. 80485, U.S.N.M.
	2.	Small right valve from which the marginal spines have mostly been broken away. Note the numerous small and embryonic specimens of a Mesonacid showing on and through the thin shell. Paratype, Cat. No, 80485, U.S.N.M.