Page:Walcott Cambrian Geology and Paleontology II.djvu/204

DESCRIPTION OF PLATE 19
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Ottoia prolifica Walcott				128
	Fig.	1.	(✕ 2.) A small specimen enlarged to show the hooks about the mouth, proboscis, and posterior end, also the distinct annular lines and segments. U. S. National Museum, Catalogue No. 57619.
		2.	(Natural size.) An adult annelid showing the enteric canal and mouth, with the proboscis broken off. U. S. National Museum, Catalogue No. 57620.
		3.	(✕ 2.) Posterior end of a small specimen in which the annular lines and hooks are very distinct. U. S. National Museum, Catalogue No. 57621.
		4.	(✕ 3.) Enlargement of a proboscis, belt of hooks, and a portion of the anterior end of the body. The outlines of the enteric canal are clearly defined as well as the belt of hooks and the papillæ on the proboscis. U. S. National Museum, Catalogue No. 57622.
		5.	(Natural size.) Adult annelid preserving very distinctly the annular lines and segments, ring of hooks, and proboscis. U. S. National Museum, Catalogue No. 57623.
Selkirkia major (Walcott)				120
	Fig.	6.	(✕ 3.) A flattened tube with the anterior portion of the animal projecting from it. U. S. National Museum, Catalogue No. 57624.
Hyolithes carinatus Matthew				121
	Fig.	7.	(✕ 2.) Ventral view of shell, operculum and fin or arm supports. This is one of a number of specimens showing the curved fin supports. U. S. National Museum, Catalogue No. 57625.
Selkirkia fragilis (Walcott)				122
	Fig.	8.	(✕ 2.) Typical form of the tube as it is flattened in the shale of locality (14s) Middle Cambrian: about 2300 feet (701 m.) above the Lower Cambrian and 2700 feet (823 m.) below the Upper Cambrian, in the Ogygopsis zone of the Stephen formation, at the great "fossil bed" on the northwest slope of Mount Stephen, above Field on the Canadian Pacific Railway, British Columbia, Canada. U. S. National Museum, Catalogue No. 57626.
Selkirkia gracilis (Walcott)				122
	Fig.	9.	(Natural size.) Type specimen, flattened in the shale. U. S. National Museum, Catalogue No. 57627.

With the exception of fig. 8, all of the specimens illustrated on this plate are from locality (35k) Middle Cambrian: dark siliceous shale in the Burgess shale member of the Stephen formation on the west slope of the ridge between Mount Field and Wapta Peak, one mile (1.6 km.) northeast of Burgess Pass, above Field, British Columbia.