lO 



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 seti/era, Hall, 

 Crania spinigera, Hall, 

 Lingula gibbosa. Hall, . 

 Pholidops ovalis. Hall, 

 Orthis hybrida, Sowerby, 

 Orthis eleganiula, Dal man, 

 Orthis subnodosa, Hall, . 

 Orthis biloba, Linnaeus, 

 Streptorhynchus ienue, Hall, . 

 Streptorhynchus subplanutn, Conrad, 

 Strophomena rhomboidalis, Wilckens, 

 Strophodont a profunda. Hall, 

 Strophonella striata, Hall, 

 Sirophonella semi/asciata, Hall, 

 Leptana trans7iersalis, Dalman, 

 Streptis waldronensis. Miller and Dyer, 

 Chonetes nonia-scotica. Hall, 

 Chonetes undulata, Hall, 

 Eichwaldia reticulata, Hall, 

 Pentamerus fornicatus, var.. Hall, 

 Anastrophia internascens. Hall, 

 Rhynchonella neglecta, Hall, 

 Rhynchonella acinus. Hall, 

 Rhynchonella indianensis. Hall, . 

 Rhynchonella whitii, Hall, 

 Rhynchonella stricklandi, Sowerby, 

 Rhynchotreta cuneata, Dalman, 



One embryo. 



No young shells obtained. 



Numerous inchoate specimens. 



II i( 



No young shells obtained. 

 II II 



II II 



Full series, showing development. 



It II 



No young shells obtained. 



Full series, showing development. 



No young shells obtained. 



II II 



One embryo. 



No young shells obtained. 



II II 



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 



