Page:Walcott Cambrian Geology and Paleontology II.djvu/185

NO. 5 Observations.—This beautiful species recalls in its dorsal aspect the recent Palmyra aurifera and Chlœia euglochis Ehlers. The latter has almost the same grouping of setæ on the parapodia.

The species is represented by a number of specimens, but none exhibit the detailed structure of the head.

Formation and locality.—Middle Cambrian (35k) 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.

This species differs from C. spinosa in being more elongate, slender, and with much smaller bundles of finer setæ. Its characters are well illustrated by figs. 1 and 3. A series of 36 specimens indicate that the elongate forms represented by figs. 1 and 2 are connected by numerous gradations with the form represented by fig. 3.

Formation and locality.—Middle Cambrian: (35k) Burgess shale member of the Stephen formation, on the west slope of the ridge between Mount Field and Wapta Peak, one mile (1.6 knu) northeast of Burgess Pass, above Field, British Columbia.

A slender form with only two strong setæ on each very short parapodia. Finer setæ may occur, but they are not shown on the one specimen which, in size and distance of the parapodia, resembles the specimen represented by fig. 2, pl. 23.

Formation and locality.—Middle Cambrian: (35k) 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.

This species is proposed to include a small chætiferous annelid not over 10 mm. in length. One specimen shows a bundle of very fine setæ on each side near the head.

Formation and locality.—Middle Cambrian: (35k) 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.