814 



CAMBRIAN BRACHIOPODA. 



A crof/iyra— Continued . 



evolution discussed 319 



evolution of 317 



general geographic and stratigraphic distribution otthe 



species referred to 106 



general stratigrapliic distribution and number of 



Cambrian species and varieties of lU 



number of species of in different types of sediment 160 



pedicle tube discussed 314 



position assumed by shells in settling to the bottom 



discussed 716 



reference to, of Acrothyra minor discussed 717 



reference to, of Acroireta inflata discussed 691 



reference to, of some of Matley's species discussed 703 



surface ornamentation discussed 301, 302 



type species "Acrotrrta proavia " 716 



vascular markings discussed 311 



minor, described 717 



general geograpliic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXXVI, fig. 4 



proavia , described 717 



compared with Acrothyra signata 719 



Acrothyra signata orta 719 



general geographic and stratigraphic distribution 



tabulated 108 



position assumed by shells in settling to the bottom 



discussed ^1" 



type specimen not figured. 



varieties discussed 716 



"proavia crossa," discussed 717 



"proavia pritni," discussed 717 



sera, described 718 



compared with A crotliyra signata prima 720 



general geographic and stratigrapliic distribution 



tabulated 106 



species and varieties referred to, discussed 716 



type specimen not figured. 



signata, described 719 



compared with A crothyra proavia 718 



A crothyra sera 718 



Acrothyra signata orta 719 



Acrothyra signata prima 720 



general geographic and stratigraphic distribution 



tabulated 106 



type specimen figured PI. LXXX, fig. 1 



varieties discussed 716 



signata orta, described 719 



general geograpliic and stratigrapliic distribution 



tabulated 106 



type specimen figured PI. LXXX, fig. 3a 



signata prima, described 720 



general geographic and stratigrapliic distribution 



tabulated 106 



type specimen figured PI- LXXX, fig. 2 



[ sera," compared with "Acrotreta papiUata" 716 



reference to Acrothyra sera discussed 716,718 



"signata tarda," reference to Acrothyra sera discussed 716,718 



Acrotreta, described 671 



cardinal area discussed 305 



classification of 321, 324 



compared with A crothele 314, 631, 633 



Acrothcle and ^ crothyra 313 



A crothele decipiens 644 



Acrothcle matthewi 648 



Acrothcle (Redlichella) granulata 712 



Acrothyra 716 



Botsfordia 602 



Diccllomus 312. 672 



Discinolepis granulata 664 



Linnarssonella 665 



Linnarssonella minuta 668 



Quebecia 611 



Schizopholis 314,602,608 



evolution discussed 319 



evolution of ^ 317 



general geographic and stratigraphic distribution of 



the species referred to 105-106 



general stratigraphic distribution and number of Cam- 

 brian species and varieties of Ill 



Acroireta— Continued. 



geograpliic and stratigrapliic distribution discussed . . 674 



mentioned 312, 527, 686, 687, 715 



muscle scars discussed 312 



number of Ordovician species and varieties of 113 



number of species of, in different types of sediment. . 160 



oldest species 701 



only species from upper Mississippi Valley 711 



pedicle tube discussed 314 



position assumed by shells in settling to the bottom 



discussed 716 



reference to, of Acrotreta inchoans discussed 690 



reference to, of Acrotreta inflata discussed 691 



reference to, of some of Matley's species discussed 703 



surface ornamentation discussed 301, 302, 674 



type species Acrotreta subconica 673 



argenta, described 674 



compared with Obolclla : 673 



Obolus 673 



general geographic and stratigraphic distribution 



tabulated 105 



muscle scars discussed 313 



type specimen figured PI. LXVII, fig. 6b 



oftereuate, described 675 



compared with Acrotreta deflnita 683 



Acrotreta gemma 685 



Acrotreta idahoensis alta 689 



Acrotreta kutorgai 692 



Acrotreta microscopica missouriensis 694 



Acrotreta ophirensis 697 



Acroireta priwseva 700, 701 



false area in, discussed 674 



general geographic and stratigraphic distribution 



tabulated 105 



position assumed by shells in settling to the bottom 



discussed 716 



type specimen figured PI. LXIV, fig. 1 



aitenuata var.?, described 676 



general geographic and stratigraphic distribution 



tabulated 105 



type specimen figured PI. LXV, fig. 2 



babel, described 676 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type specimen figured PI. LXXVII, figs. 6 and 6a 



baileyi. described 676 



discussed 673 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type sp3cimen figured PI. LXXVII, fig. 2 



bellatula, described 677 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type specimen figured PI. LXXVm, fig. 4 



belli, described 678 



general geographic and statigraphic distribution tab- 

 ulated 105 



type specimen figured PI. LXXVII, fig. 8 



bisecta. described 678 



compared with A crotreta kutorgai 692 



Acrotreta sabrinx 703 



Obolus ( Wesionia) ella 674 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type specimen not figured. 



?? cancellata, described 679 



general geographic and stratigraphic distribution tab- 

 ulated 106 



surface ornamentation discussed 302, 672 



tj-pe specimen figured PI. LXXIX, fig. 6 



carinata , described 679 



compared with Acrotreta circularis 680 



general geographic and stratigraphic distribution tab- 

 ulated 105 



type specimen figured text figs. 56A-C, 680 



circularis, described 680 



compared with Acrotreta carinata 680 



general geographic and stratigrapliic distribution tab- 

 ulated 105 



type specimen figured text figs. 57A-D, 680 



