OLENELLUS AND OTHER GENERA OF MESONACID.E 4I I 



OlcncUus canadensis, new species (continued) : page 



8. Fragment of the telson. Natural size. Locality (35/;), Mt. Bos- 

 worth. British Columbia. U. S. National Museum, Catalogue 

 No. 56814^. 



9 and 10. Fragments of the pleural lobe of thoracic segments. 

 Natural size. 9 = locality 583'; 10 ^locality 35/1; both on 

 Mt. Bosworth, British Columbia. U. S. National Museum, 

 Catalogue Nos. 56816a and 56814^, respectively. 



II. A minute cephalon associated with this species and referred to 

 it. X 8. Locality (35/). Ptarmigan Pass, Alberta. U. S. 

 National Museum, Catalogue No. 568170. 



Callavia ? nevadensis, new species 285 



Fig. 12. Portion of a cephalon showing the broad frontal limb, narrow 

 glabella, and relatively short eye lobe as compared with Olenel- 

 lus gilberti. Natural size. Locality (52), Prospect Mountain, 

 Eureka District, Nevada. U. S. National Museum, Catalogue 

 No. 56799a. 



Figure 12 is copied from Walcott, 1884, pi. 9, fig. 16, where 

 this specimen is referred to OlcncUus gilberti. 



13. Fragments of the under side of a cephalon in which the genal 



angles are carried far forward as in O. frernonfi (pi. 37, figs. 

 8-12). Natural size. Locality (313^), south end of Timpa- 

 hute Range, Nevada. U. S. National Museum, Catalogue No. 

 56800a. 



Figure 13 is copied from Walcott, 1886. pi. 19, fig. 2d, where 

 the specimen is referred to OlcncUus gilberti. 



14. Outline of a sm.all cephalon showing broad frontal limb and 



normal type of genal angles. Natural size. Locality (51), 

 summit of Prospect Mountain, Eureka District, Nevada. U. 

 S. National Museum, Catalogue No. 56799^. 



Figure 14 copied from Walcott, 1884, pi. 21, fig. 13, where 

 the specimen is referred to OlcncUus gilberti. 



IVaniicria ? gracile, new genus and new species 298 



Fig. 15. An hypostoma associated with specimens of the cephalon of 

 this species. X 2. Locality (177), west of Deep Spring 

 Valley, Inyo County, California. U. S. National Museum, 

 Catalogue No. 56802a. 



16. A thoracic segment associated with the hypostoma illustrated 



by fig. 15. This has the pleural furrow of IVanncria but the 

 spinous termination is more like that of H'^hnia. Same locality 

 as fig. 15. U. S. National Museum, Catalogue No. 568026. 



17. Left side of cephalon showing strong border, and slender genal 



spine. X I-5- U. S. National Museum, Catalogue No. 56803a. 



18. Fragment of the front part of the cephalon. X i-5- U. S. Na- 



tional Museum, Catalogue No. 568036. 

 16 — w 



