Volume IX. September, l8g4. Number j. 



JOURNAL 



MORPHOLOGY 



/ 



OBSERVATIONS ON THE GEMMULE AND EGG 

 DEVELOPMENT OF MARINE SPONGES. 



HENRY V. WILSON.! 



TABLE OF CONTENTS. 



Page 



Introduction 278 



I. Adult Structure and Gemmule Development of Esperella 



FIBREXILIS, N. SP. 



1. Adult 279 



Ejitbryological Alethods 28 5 



2. Formation of Gemmules 2S7 



3. Development of Gemmule into Swimming Larva 294 



4. Metamorphosis 298 



Ectoderm 301 



Siibdermal cavities and canals 305 



Vertnal tfiembrane 307 



Efferent canals and oscula 308 



Afferent canals and pores 309 



Flagellated chambers 310 



Spicules 314 



Summary of the leading facts in the gemmule development of 



Esperella 315 



Previoits knowledge of the development of Esperia {Esperella).. 316 



! Published by permission of Hon. Marshall McDonald, U.S. Commissioner of 

 Fish and Fisheries. 



