10 



INTRODUCTION 



common species which has afforded no young shells. Whitfieldia maria, 

 another abundant form, furnishes a series which is notably incomplete, as 

 the youngest individual observed, which can with certainty be referred to it, 

 has a length of 6 mm. Likewise, the inarticulate species have yielded 

 almost no immature specimens. 



LIST OF THE BRACHIOPODA OCCURRING IN THE NIAGARA SHALES AT 



WALDRON, INDIANA 



Crania siluriana, Hall, 

 Crania set if era, Hall, . 

 Crania spinigera, Hall, 

 Lingula gibbosa, Hall, . 

 Pholidops ovalis, Hall, 

 Or this hybrida, Sowerby, 

 Or this elegantiila, Dal man, 

 Orthis subnodosa, Hall, . 

 Orthis biloba, Linnaeus, 

 Streptorhynchus tenue, Hall, . 

 Streptorhynchus subplanum, Conrad, 

 Strophomena rhomboidalis, Wilckens, 

 Strophodonta profunda. Hall, 

 Strophonella striala, Hall, 

 Strophonella semifasciata, Hall, . 

 Leptana Iranmersalis, Dalman, 

 Streptis waldronensis, Miller and Dyer, 

 Chonetes nova-scotica, Hall, 

 Chonetes undulata, Hall, 

 Eichwaldia reticulata, Hall, . 

 Pentamerus fornicaitts, var., Hall, 

 Anastrophia iniernascens. Hall, 

 Rhynchonella neglecta, Hall, 

 Rhynchonella acinus, Hall, 

 Rhynchonella indianensis, Hall, . 

 Rhynchonella ivhitii, Hall, 

 Rhynchonella stricklandi, Sowerby, 

 Rhynchotreta cuneata, Dalman, 



One embryo. 



No young shells obtained. 



Numerous inchoate specimens. 



t t u 



No young shells obtained. 



u u 



ti u 



Full series, showing development. 



it it 



No young shells obtained. 



Full series, showing development. 



No young shells obtained. 



it u 



One embryo. 



No young shells obtained. 



u u 



Young shells not rare. 

 No young shells obtained. 

 Young shells not rare. 

 Young shells very abundant. 



Mature form abundant; no young shells obtained. 

 Young shells common. 



