. Smithsonian miscellaneous collections . 3c. (X 2.) Cranidium and pygidium for comparison with thoseof Albertella helena. U. S. National Museum, CatalogueNos. 53413 and 53415. The figs. 3b, 3c are after Walcott,Smithsonian Misc. Coll., Vol. 53, 1908, pi. 1, figs. 4 and 6. The specimens represented by figs. 3b and 3c are from (Locality35c) Middle Cambrian: Ptarmigan formation (Ross Lake shale);Mount Bosworth, British Columbia. 3d. (X 12.) Matrix of a minute cranidium impressed on the sur-face of a valve of Wimanella simplex. U. S. NationalMuseum, Catalogue No. 63764. From locality 63J, associa
. Smithsonian miscellaneous collections . 3c. (X 2.) Cranidium and pygidium for comparison with thoseof Albertella helena. U. S. National Museum, CatalogueNos. 53413 and 53415. The figs. 3b, 3c are after Walcott,Smithsonian Misc. Coll., Vol. 53, 1908, pi. 1, figs. 4 and 6. The specimens represented by figs. 3b and 3c are from (Locality35c) Middle Cambrian: Ptarmigan formation (Ross Lake shale);Mount Bosworth, British Columbia. 3d. (X 12.) Matrix of a minute cranidium impressed on the sur-face of a valve of Wimanella simplex. U. S. NationalMuseum, Catalogue No. 63764. From locality 63J, associated with figs. 3, 3a. Albertella helena Walcott 39 Fig. 4. (Natural size.) A nearly entire dorsal shield, the type speci-men. U. S. National Museum, Catalogue No. 53410. Thefig. 4 is after Walcott, Smithsonian Misc. Coll., Vol. 53,1908, pi. 2, fig. 1. The specimen represented by fig. 4 is from (Locality 5J) MiddleCambrian: Gordon shale; Scapegoat Mountain, Powell County,Montana. SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 67, NO. 2, PL. 7. CAMBRIAN TRILOBITES NO. 2 ALBERTELLA FAUNA IN BRITISH COLUMBIA AND MONTANA 59 Albertella Helena Walcott—Continued. pack 5. (X2.) A dorsal shield with a more perfect cephalon than thaton fig. 5a. A matrix of a fine pygidium occurs just below onthe same fragment of rock. U. S. National Museum,Catalogue No. (X 3.) A nearly entire dorsal shield. U. S. National Museum,Catalogue No. 63766. The specimens represented by figs. 5, 5a are from the siliceousshales of (Locality 63J) Middle Cambrian: Ptarmigan formation(Ross Lake shale) ; above Ross Lake, British Columbia. Zacanthoides ? cimon Walcott 41 Fig. 6. (X 3.) Cranidium preserved in limestone. U. S. NationalMuseum, Catalogue No. (X 3.) Fragment of an associated pygidium. U. S. NationalMuseum, Catalogue No. 63768. From locality 63b, Middle Cambrian: Ptarmigan formation;Ptarmigan Peak, Alberta. Vanuxemella nortia Walcott 37 Fig. 7. (X 2.) A nearly entire dorsal shield somewhat c
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