856 



CAMBRIAN BEACHIOPODA. 



Obolus ( Miekwitzella)— Continued. 



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



stratigraphic range mentioned 379 



type species " Obolus siluricus" 378,434 



siluricus, described 434 



compared witb Obolus dolatus 390 



Obolus (A-critis) antiquissimus 439 



general geographic and stratigraphic distribution 



tabulated 101 



surface ornamentation discussed 301 



type specimen not figured. 



Obolus (Palseobolus) , described 426 



characterized 378 



classification of 321, 323 



discussed 427 



evolution discussed 318 



evolution of 317 



general geographic and stratigraphic distribution of 



the species referred to 101 



general stratigraphic distribution and number of 



Cambrian species and varieties of , . 110 



number of species of, in different types of sediment 160 



stratigraphic range mentioned 379 



type species "Palseobolus bretonensis " 378, 426 



hretoneTisis, described 426 



compared with Lingulella (Lingulepis) rowei 558 



Obolus acadicus 380 



Obolus (Palseobolus) bretonensis lens 427 



general geographic and stratigraphic distribution 



tabulated 101 



type specimen figured PI. XXXII, fig. 5 



bretonensis lens, described 427 



general geographic and stratigraphic distribution tab- 

 ulated 101 



type specimen not figured. 



bretonensis lens longits, discussed 427 



Obolus (Schmidfia), described 441 



characterized 378 



classification of 321, 323 



compared with" Acritis," " Euobolus/' a,nd" Thpsano- 



tos" by Mickwitz , 434 



Lingulella 472 



Lingulella (Leptembolon) Ungul^formis 543 



evolution of 317 



general geographic and stratigraphic distribution of 



the species referred to lOl 



general stratigraphic distribution and nimiber of Cam- 

 brian species and varieties of no 



mentioned 318, 375, 471 



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



relative position of vascular sinus in species of 376 



species and varieties recognized by Mickwitz, listed . . 380 



stratigraphic range mentioned 379 



thickening of shell beneath visceral area discussed 310 



type species " Schmidtia celata" 378,442 



acuminatus, described 442 



compared with B icia gemma 570 



Obolus (Schmidtia) crassus 447 



general geographic and stratigraphic distribution tab- 

 ulated 101 



type specimen not figured. 



acuminatus alatus, mentioned 443 



celatus, described 444 



compared with Lingulella davisi 472 



Lingulella granvillensis 471 



Obolus (Schmidtia) acuminatus 443 



Obolus (Schmidtia) crassus 447, 448 



Obolus (Schmidtia) obtusus 449, 450 



general geographic and stratigraphic distribution tab- 

 ulated lOlj 



netlike coating of, which resembles a bryozoon 445 



type specimen not figured. 

 celatus orbiculatus, compared with Obolus (Acritis) antiquis- 

 simus 440 , 



mentioned 445 



celatus prsEcisus, compared ^vith Obolus (Schmidtia) acumi- 

 natus 443 



mentioned 445 



Obolus (Schmidtia) cras5M5, described 464 



compared with Obolus tetonensis ninus 418 



Obolus (Schmidtia) acuminatus 443 



Obolus (Schmi dtia) obtusus 449 



general geographic and stratigraphic distribution tabu- 

 lated 101 



type specimen not figured. 



obtusus, described " 448 



compared with Obolus (Schmidtia) acuminatum 443 



Obolus (Schmidtia) celatus 445 



Obolus (Schmidtia) crassus 447 



general geographic and stratigraphic distribution tabu- 

 lated 101 



type specimen not figured. 



obtusus longus, mentioned 449 



"Obolus (Thysanotos) siluricus," compared witii Oboltbs (Acritis) 



antiquissimus 377-378 



Obolus ( Westonia), described 450 



characterized 378 



classification of 321, 323 



compared with A crothele 631 



Botsfordia 602 



Schizambon ? esthonia 622 



evolution discussed 318 



evolution of 317 



general geographic and stratigraphic distribution of 



the species referred to 101 



general stratigraphic distribution and number of Cam- 

 brian species and varieties of 110 



mentioned 379 



muscle scars discussed ', 312 



number of Ordoviciau species and varieties of 113 



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



relative position of vascular sinus in species of 376 



species referred to classified according to surface orna- 

 mentation 450-451 



stratigraphic range mentioned 379 



surface ornamentation discussed 301, 302 



type species "Lingula aurora" 378,450 



alandensis, described 451 



general geographic and stratigraphic distribution tabu- 

 lated 101 



surface ornamentation characterized 451 



type specimen figured PI. XL VIII, fig. 6a 



aurora, described 451 



compared with Lingulella (Lingulepis) starri 559 



Obolus mcconnclU 396 



Obolus ( Westonia) ella 456 



Obolus (Westonia) euglyphus 461,462 



Obolus ( Westonia) stoncanus 465,466 



general geographic and stratigraphic distribution 



tabulated 101 



suri'ace ornamentation characterized 301,450,451 



type specimen not figured. 



balticus, described 453 



compared with Obolus ( Westonia) Alandensis 451 



Obolus ( Westonia) blackwelderi 453 



general geographic and stratigraphic distribution 



tabulated 101 



stratigraphic position of bowlder containing, dis- 

 cussed 454 



surface ornamentation characterized 451 



type specimen figured PI. XLVIII, fig. 7b 



blackwelderi, described 453 



general geographic and stratigraphic distribution 



tabulated 101 



type specimen figured PI. XXXIX, fig. 10 



bottnicus, described 454 



compared with Obolus ( Westonia) Alandensis 451 



Obolus ( Westonia) eloTigatus 459 



Obolus ( Westonia) finlandensis 462, 684 



Obolus ( Westonia) wimani 467 



general geographic and stratigraphic distribution 



tabulated ' . . 101 



stratigraphic position of bowlder containing, dis- 

 cussed 451, 454, 684 



surface ornamentation characterized 451 



type specimen figured PI. XLVIII, fig. 4 



