xiv CONTENTS 



Paoe 



4. Development of some Silurian Brachiopoda — Con- 

 tinued 



Mature Form 331 



Incipient Shell 331 



Developmental Changes 331 



Mimulus waldronensis Miller and Dyer, 1878 . . 334 



Dictyonella reticulata Hall, 1868 ... ... 335 



Anastrophia internascens Hall, 1879 . ... 337 



Specific Characters . 337 



Mature Form 337 



Incipient Form 338 



Developmental Changes . 338 



Camarotcechia acinus Hall, 1863 339 



Specific Characters 340 



Mature Form 340 



Variations from the Normal Adult .... 340 



Initial Shell ... 340 



General Developmental Characters 341 



Camarotcechia neglecta Hall, 1852 341 



Specific Characters 342 



Mature Form 342 



Incipient Form 343 



Developmental Variations 343 



General Form and Outline 343 



Beak and Foramen 343 



Plications 343 



Camarotcechia Whitii Hall, 1863 344 



Specific Characters .... 344 



Mature Form 344 



Abnormalities at Maturity 345 



Incipient Form 345 



Developmental Variations 345 



General Form and Outline 345 



Beak and Foramen 346 



Plications 346 



Camarotcechia indianensis Hall, 1863 346 



Specific Characters 347 



Normal Mature Form 347 



Variations from the Normal 348 



A. Forms with one plication in the ven- 



tral sinus 348 



B. Forms with three plications in the 



ventral sinus 348 



C. Forms with four plications in the ven- 



tral sinus 348 



Monstrous Forms 348 



Initial Shell 349 



