OLENELLUS AND OTHER GENERA OF MESONACID^ 



Oleiicllus — Continued. page 



anterior glabellar lobe in 242, 243 



cause of enlargement of third segment in 245 



compared with Mesonacis 304 



Ncvadia 256 



Pccdeumlas 304 



delimitation of genus 248 



development of, shown in diagram 249 



followed by Parad oxides 313 



eye lobes in 239 



eyes of, compared with those of Litniilus 240, 327 



genal and intergenal spines in 237 



geographic distribution of 252, 253, 314 



line extinct in Lower Cambrian time 249 



maculae on hypostoma of 244 



mentioned. .233, 234, 236, 244, 247, 250, 256, 263. 306, 317, 323, 342 



non-occurrence on Asiatic continent 314 



preceded by Paradoxides [Whitfield] 313 



segmentation of cephalon 238 



species referred to the genus listed 232 



stage in development of thorax defined 245 



stages passed through in development 245, 313 



stratigraphic distribution tabulated 251 



telson of, compared with that of Limnlus 246, 312 



telson not a pygidium 24b 



telson the median spine of Pcedeumias 245 



zone, defined 250 



argentus, new species 314, pi. 40, figs. 12-16 



associated fossils listed 315 



compared with Olenellus frononti 315 



Peachella iddingsi 315 



mentioned 248, 314 



stratigraphic distribution tabulated 251 



asaphoidcs Bernard, in synonymy 271 



Ford, in synonymy 270 



Hall, in synonymy 269 



Holm, in synonymy 270 



Lesley, in synonymy 270 



Lindstrom, in synonymy 272 



Matthew, in .synonymy 271 



Walcott, in synonymy 270 



broggeri Bernard, in synonymy 279 



Walcott, in synonymy 279 



callavei Lapworth, in synonymy 2S2 



canadensis, new species 316, pi. 38, figs, i-io 



associated fossils listed 318 



compared with Olenellus fremonti 317, 318 



Olenellus gilberti 318 



Olenellus gilberti, var 331 



