852 



CAMBRIAN BRACHIOPODA. 



O&oitts— Continued . 



general geographic and stratigraphic distribution of 



the species referred to 99, 100 



general stratigraphic distribution and number of Cam- 

 brian species and varieties of 110 



geographic distribution discussed 379-380 



Hall and Clarke on development of 309 



largest and most recent species of 392 



latest American species of 386 



mentioned. 310, 381, 386, 387, 388, 389, 392, 403, 405, 407, 408, 



409, 411, 413, 414, 422, 423, 428, 435, 436, 439, 441,442, 463,470, 



471, 472, 473, 474, 475, 478, 489, 503, 505, 527, 531, 532, 541, 590 



muscle scars compared with those of Neotremata. . . 312, 313 



muscle scars discussed 312 



number of Ordovician species and varieties of 113 



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



pedicle furrow discussed 314 



reference to, of Acrotreta? minima, discussed 695 



relative position of vascular sinus in species of 376 



shell structure of compared with that of Lingula 296 



species and varieties recognized by Mickwitz listed. . . 380 



stratigraphic range discussed 378-379 



subgenera characterized 377-378 



subgeneric criteria 376 



surface ornamentation discussed 302 



type species discussed 373 



type species Obolus apoUinis 373 



umbonal muscle mentioned 313 



vascular markings discussed 311 



acadicibs, described 380 



confused with Lingulclla concinna 3S0 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen figured PI. XI, fig. 5 



f advenus, described 380 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen figured PI. XII, fig. 5 



sequiputeis, identical with Obolus selwyni 414 



anceps, described 380 



compared with Obolus nundina 406 



Obolus s-^. undt. e 423 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen iigured PI. S, fig. 3b 



f av^illus, described 381 



compared with Obolus fmirandus 405 



general geographic and stratigraphic distribution tab- 

 ulated 99 



I type specimen figured PI. XII, fig. 2 



apolUnis, described 381 



cardinal area discussed 304 



compared with Bicia 568 



Elkania desiderata 562 



Lingulella acutangula 472, 474, 475 



Linnarssonella minuta 668 



Neobolus war.thi 564 



Obolclla ckromatica 592 



Obolella crassa 594 



Obolus apollinis ingricus 384 



Obolus apoUinis quenstedti 385 



Obolus feistmanteli 391 



Obolus prindlei 379 



Obolus (Fordinia) bellulus 562 



Obolus (Lingulobolus) 431 



Obolus ( Westonia) escasoni 460. 472 



Siphonotreta unguiculata 625 



general geographic and stratigraphic distribution tab- 

 ulated 99 



interior features discussed 372, 373 



muscle scars discussed 312 



old-age characters discussed 315 



platform discussed 310 



shell sections figured text figs. 4, 15, and 15a, 299 



thickening of shell beneath visceral area discussed. . 309-310 



tubules of, discussed 300 



type of Obolus 373 



type specimen not figured. 



vascular markings discussed 311 



Obolus apollinis ingricus, described 384 



compared with Obolus apollinis maximus 384 



Obolus apolUnis quenstedti 385 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen not figured. 



apollinis maximus, described 384 



compared with Obolus apollinis quenstedti 385 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen not figured. 



apollinis quenstedti, described 384 



compared with Obolus mativMis 401 



Obolus mickwitzi 404 



Obolus selwyni 414 



bolus (Mickwitzella) siluricu s 435 



figured 374 



general geographic and stratigraphic distribution tab- 

 ulated 99 



type specimen figured text fig. 34A, 374 



? bavaricus, described 385 



compared with Lingulella wirtM 541 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured PI. XV, fig. 10 



belli, described 386 



general geographic and stratigraphic distribution tab- 

 ulated. 100 



type specimen figured PI. XXXVIII, fig. 3 



chinensis, described : 387 



compared with Obolus obscurus 406, 407 



Obolus prindlei 409 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured PI. XXXIX, fig. 7 



complexus, described 387 



compared with Obolus f advenus 380 



Obolus f rokitzanensis 411 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured PI. XII, fig. 3 



cyane, described 388 



compared with Lingulella iole 508 



Obolus ( Westonia) rogersi 464 



general geographic and stratigraphic distribution tab- 

 ulated 100 



stratigraphic position of, discussed 389 



thickening of the shell beneath the visceral area dis- 

 cussed ., 310 



type specimen figured PL XXVII, fig. 4 



damesi, change in generic reference 489 



discoidcus, described 389 



compared with Obolus wortheni 421 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured PI. XVIII, fig. 6c 



dolatus, described : 390 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured text fig. 35A, 390 



eichwaldi, described 390 



compared with Obolus volbortM 419 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen not figured. 



elegant, described 390 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen not figured. 



feistmanteli, described 391 



compared "with Obolus complexus 388 



Ooolus membranaceus 402 



Obolus ? mirandus 405 



general geographic and stratigraphic distribution tab- 

 ulated 100 



type specimen figured PI. XII, fig. Id 



fragilis, described 392 



compared with Lingulella bellula 482 



Obolus refulgens 410 



