Page:Walcott Cambrian Geology and Paleontology II.djvu/310

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218
SMITHSONIAN MISCELLANEOUS COLLECTIONS
VOL. 57
DESCRIPTION OF PLATE 29
PAGE
Molaria spinifera Walcott 200
Fig. 1. (✕3.) Side view in which the thoracic pleuræ of the segments have been broken away so as to show appendages. U. S. National Museum, Catalogue No. 57688.
2. (✕3.) Dorsal view. U. S. National Museum, Catalogue No. 57689.
3. (✕3.) Ventral view, showing some of the gills (br), liver (k) beneath the cephalic shield, and alimentary (al) canal. The ends of the thoracic segments (ths) are marked by fine lines. U. S. National Museum, Catalogue No. 57690.
4. (✕3.) Dorsal view. Minute appendages show from beneath abdominal segment, also setiferous joints of the thoracic legs. U. S. National Museum, Catalogue No. 57691.
5. (✕3) Dorsal view. a' = antennules. U. S. National Museum, Catalogue No. 57692.
Habelia optata Walcott 202
Fig. 6. (✕2.) Side view of a specimen flattened in the shale. Three of the setiferous legs near the head have been pushed out above the body. U. S. National Museum, Catalogue No. 57693.
Yohoia tenuis Walcott 172
Fig. 7. (✕2.) Side view showing the pleuræ of the thorax and traces of the appendages of the head. U. S. National Museum, Catalogue No. 57694.
8. (✕3.) Specimen with abdomen and expanded rami forming a swimming tail. U. S. Museum, Catalogue No. 57695.
9. (✕2.) Fragment of thorax and head, showing segmentation of thorax, eyes, antennule in center and part of a large antenna. The latter has its spiniferous terminal joint turned down towards the eye on the right side (upper in drawing). U. S. National Museum, Catalogue No. 57696.
10. and 11. (✕2.) Small specimens seen from above. U. S. National Museum, Catalogue Nos. 57697 and 57698.
12. (✕2.) Side view of a specimen showing segmentation of head and thorax; antenna and portions of thoracic appendages. U. S. National Museum, Catalogue No. 57699.
13. (✕3.) The anterior half of figure 12, still further enlarged.
Yohoia plena Walcott 173
Fig. 14. (✕3.) A small specimen showing the general form of the species. Better specimens have been found since the plate was prepared and will be illustrated in a future paper. U. S. National Museum, Catalogue No. 57700.

All of the specimens illustrated on Plate 29 are from locality (35k) Middle Cambrian: 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.