INDEX. 



The references in heavy=faced type refer to the locality numbers and the 

 pages upon which the genera and species are described and figured. 



PAGE 



Abdominal sheath 426 



Acanthodictya hispida Hinde 268 



Acrocephalitcs gentius Walcott 473 



Acrothele clitus Walcott 70, 480 



figured, pi. 10, figs. 4, 4<i-c 108 



colleni Walcott 21 



pretiosa 268 



sp 467 



Acrothyra gregaria, new species, Middle Cambrian, described 498 



figured, pi. 122, figs. 9-12 55° 



signata Matthew, compared 498 



Acrotreta atticus, new species, Ozarkian, compared S 2 S 



described 496 



figured, pi. 109, figs. 10-12 537 



cf . idahoensis Walcott 473 



cf. microscopica Shumard, Ozarkian, described 497 



cf . sagittalis Salter 473 



compared with Acrothyra 498 



discoidea, new species, Ozarkian, compared 5 2 5 



described 497 



figured, pi. 109, figs. 13-14 537 



idahoensis Meek 467 



sulcata Walcott 475 



Walcott 475 



compared 49^ 



microscopica (Shumard), compared 497 



sagitallis Salter, compared 496, 497 



taconica (Walcott), Atlantic Province and Mount Whyte 



fauna 66 



transversa (Hartt) , compared 492 



sp. undt 481, 523 



Ozarkian, described 525 



spinosa Walcott, compared 497 



Adams, Frank D 10 



Agassiz, Dr. Alexander 205 



study of Limulus 123 



Prof. Louis 116 



Agnostus a 475 



b 475 



sp 471, 473 



sp. ? 467 



555 



