CONTENTS xvii 



Page 



5. Development of Bilobites ... ... 399 



Developmental Changes in DHobites various . . 402 



Observations . . . . . 404 



('). Development of Terebratalia obsoleta Dall 40G 



7. Develoi'ment of the Brachial Supports in Die- 



LASMA AND ZvaOSPIRA . . . 410 



Development of the Loup in Dtelasma turgidum . 412 

 Development of the Brachial Supports in Zygospira 



recurvirostris .... 413 



Observations and Correlations . . . 415 



IV. MISCELLANEOUS STUDIES IN DEVELOPMENT 



1. Development of a Paleozoic Poriferous Coral . . 421 



Development of Pleurodictyum lenlicidare . . A'ri 



General Conclusions . . . . . 42.5 



2. Symmetrical Cell Development in the FaaositidjE 429 



Summary . .... 433 



8. Development of the Shell in the Genus Tor- 



noceras Hyatt . . . . 435 



V. PLATES AND EXPLANATIONS. ... .441 



INDEX . . 597 



