48 RESEARCH IN CHINA. 
tion from a photograph of a Hyolithes (H. carinatus Matthew) that shows 
the operculum in position, also the support of the fin-like arms so character- 
istic of recent pteropods. 
Cephalopoda.—One genus and one species from a horizon 480 feet (146 m.) 
below the summit assigned to the Upper Cambrian are all that are known of 
this class. The species Cyrtoceras cambria (C56) [plate 6, figs. 4, 4a—-c] is a 
typical example of the family Cyrtoceride and from its presence we are com- 
pelled to consider that there was a large and varied cephalopod fauna in the 
area, from which it migrated into the Siniansea. It isa reminder of our want 
of data on the fauna of the Upper Cambrian and of the great harvest to be 
gathered by the future field-worker and student of the stratigraphic geology 
of Asia. 
In the Ozark region of Missouri in North America Ulrich has found both 
the Cephalopoda and Gastropoda extensively developed at a horizon not 
much above that of Cyrtoceras cambria, if we base the correlation on the char- 
acter of the trilobites in the two distant localities. 
Trilobita.—The exceptional genera of the Trilobita found in China and 
not known to occur elsewhere are Stephanocare [plate 7], Teinistion [plate 9], 
Blackwelderia [plate 9], Damesella [plate 9], and Drepanura [plate ro]. All 
other genera are represented in western North America and western Europe, 
and there is a striking resemblance even to specific characters in many of the 
forms. ‘The most noticeable omissions of American and European genera 
from the Chinese fauna are Paradoxides of the Atlantic Basin fauna and 
Olenoides, Dikelocephalus, and Neolenus of the North American fauna. ‘The 
closely related genus Dorypyge (to Olenoides) is found abundantly in China, 
western United States, and on the island of Bornholm in northwestern Europe. 
The genera Ptychoparia, Conokephalina, Acrocephalites, Inouyia, A graulos, 
Iisania, Solenopleura, Anomocare, Anomocarella, and Coosia are well repre- 
sented in China, western North America, southwestern United States, and 
northwestern Europe. Bathyuriscus and Asaphiscus are essentially Pacific 
Basin types. ‘They represent the most advanced forms of the Trilobita of 
Middle Cambrian time and may be compared with Asaphus and Bathyurus 
of the Ordovician fauna. 
Redlichia is an intermediate form that serves in a limited degree to con- 
nect the Mesonacide [Walcott, 1910a] and the Paradoxide. Its tapering gla- 
bella and elongate eye-lobes recall those of Nevadia, and its small pygidium 
that of Holmia and Callavia [see Walcott, 1910a, plate 44]. 
Many species of trilobites are represented only by fragments of the 
cephalon, scattered segments of the thorax, and pygidia that can only be 
tentatively designated as probably belonging to the same species as an 
associated cephalon. In some instances the cephala of otherwise distinct 
genera are so nearly similar that in the absence of the thorax and pygidium 
they would be referred to one genus. This is particularly the case among 
the genera of the Ptychoparide. 
