Page:Proceedings of the United States National Museum, Volume 76.djvu/137

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Several rare, fragmentary valves collected at two localities in central Manchuria, constitute the material on which this species is founded. It is quite possible that they represent more than one species. Comparing the Manchurian species with those from the Burgess shale we note that in general shape it differs little from the genotype, but due to the fact that all the specimens preserve only the anterior portions of the valves nothing can be determined regarding the number and characters of the marginal spines. The reticulations are quite similar also, the smaller ones on the keel perhaps being more suddenly differentiated from those on the remainder of the test than usually occurs in the American species. It is the appearance of the keel in the two specimens illustrated that injects some uncertainty as to their specific identity, and this can only be cleared up by securing more material.

Horizon and locality.—Middle Cambrian; Huo-lien-chai and Mt. Tang-shih-ling, near Yen-tai, Manchuria.

Holotype and paratype.—Cat. Nos. 80481, 80482, U.S.N.M.

This fine Lower Cambrian species is represented in the collections by four practically complete specimens besides a few instructive fragments.

In shape and general appearance it is most like the Middle Cambrian genotype. It differs in its stronger reticulations, more particularly in its four instead of three large posterior spines—in which respect it is like T. canadensis—and most of all in the size and abundance of the spines along the dorsal line where five or more may be counted in the anterior half of the line. These spines were considerably longer than indicated in the illustrations, if the small fragment in the collections is properly interpreted as to species and position in the test. None of the specimens clearly preserve dorsal spines in the posterior third or more of the line, and since other species also lack spines in that place it may be assumed that if any were present in this species they were smaller than the anterior ones.

The specific name is given in honor of the discoverer of these interesting fossils in the Lower Cambrian of British Columbia.

Horizon and locality.—Lower Cambrian, Eager formation; (loc. 67g), near Cranbrook, British Columbia.

Holotype and paratypes.—Cat. No. 80485, U.S.N.M.

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