DEVELOPMENT OF SOME SILURIAN BRACIIIOPODA 315 



Lingula glhbosa Hall .... 

 Pholidops oualis Hall 

 Rhipidomella kybrida Sowerby 

 Dalmanella elegantula Daluian 

 Orthis subnodosa Hall . . . 

 BUobiles h'dobus Linnaeus . 

 Orthothetes tenuis Hall 

 Orlhotheies subplanus Conrad • 

 LeptcBna rhomboidalis Wilckens 

 Siropheodonta profunda Hall . 

 Strophonella striata Hall 

 Stroplwnella semifasciala Hall 

 Plectambonite.i Iransversalis Dalman 

 Mimulus waldronensis Miller andDj'er 

 Chonetes nova-scoiicus Plall . 

 Chonetes undulatus Hall 

 Dictyonella reticulata Hall . 

 Ctorinda fornicata, var., Hall . 

 Anaslrophia internascens Hall . 

 Camarotoechia neglecta HaU 

 Camarotaechia acinus Hall 

 Camarotcechia indianensis Hall 

 Camarotczchia Wkitii Hall . . 

 Uncinulus Stricklandi Sowerby 



Rliynchotreta cuneata Dalman . 

 Atrypa reticularis Linnseus 

 Zygospira minima Hall . 

 Atrypina disparilis Hall 

 Homceospira evax Hall . . . 

 Homceospira sobrina sp. n. . 

 Nucleospira pisifonnis Hall * 

 Merislina rectirostris Hall 

 Whiljieldella nitida Hall 

 Meristina Maria Hall . . 



No young shells obtained. 



U (( (( 



Numerous inchoate specimens. 

 No young shells obtained. 



Full series showing development. 



ti u u 



No young shells obtained. 



Full series, showing development. 



No young shells obtained. 



One embryo. 



No young shells obtained. 



LV it 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. 

 Young shells abundant. 

 No young shells obtained. 

 Young shells common. 

 Young shells very abundant. 

 Young shells not rare. 



ti a i( 



Full series, showing development. 

 Numerous inchoate specimens. 

 Incomplete series showing devel- 

 opment. 

 No young shells obtained. 

 Full series, showing development. 



Spirifer eudora Hall 



Spirifer crispus Hisinger 



Spirifer crispus, var. simplex. Hall . " " " 



Spirifer radiatus Sowerby .... " " " 



Reticularia bicostata, var. petila, TlaM. " " " 



* The mature characters of this species are assumed so early that the 



youngest forms observed show no important differences from the adult. On 

 this account no discussion of its characters is given in the ensuing pages. 



