except for the slightly flattened dorsal side. Operculum unknown. Shell rather thick, and with a smooth surface.
The largest specimen in the collection has a length of 5 mm.
Observations.—This species is distinguished from other Chinese forms by its rounded tube and smooth surface. It is the representative in form of the American Orthotheca communis Billings.[1]
Orthotheca glabra occurs abundantly in association with Hyolithes cybelc Walcott, in the Dorypyge richthofeni zone of Manchuria. Some of the shells have a long, slender terminal section to the tube that is more or less slightly curved. It is so slender and round that it suggests the tube of Hyolithellus.[2]
Formation and locality.—Middle Cambrian: (C71) massive cliff making limestone in the central portion of the Ki-chóu formation, 4 miles (6.4 km.) southwest of Tung-yü ; and (C72) thin green gray limestone interbedded with ocherous and green clay shales, overlying the massive oolite in the Ki-chóu formation, 4 miles (6.4 km.) east of Fang-lan-chön ; both in Shan-si, China.
Collected by Eliot Blackwelder.
Also (35n) Middle Cambrian: Fu-chóu series; limestones near the base of the series just above the white quartzite, collected in a low bluff on the shore of Tschang-hsing-tau island, east of Niang-niang-kung, Liau-tung, Manchuria, China.
Collected by J. P. Iddings and Li San.
ALBERTELLA PACIFICA, new species
Plate 14, fig. 6
Of this form only one fragment of the pygidium was found in the collection from Manchuria. This is so characteristic that I do not hesitate to identify it as the pygidium of an Albertella although stratigraphically it occurs at a higher horizon in the Middle Cambrian than the American species of the genus.
A pygidium illustrated by M. Barrande as Paradoxides desideratus Barrande[3] may possibly belong to a species of Albertella. The axial lobe of the pygidium has seven rings and a terminal section and the pleural lobes have lateral spines.
Formation and locality.—Middle Cambrian: (36f) Fu-chóu series; about 1000 feet (305 m.) above the white quartzite, collected in a
