CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 

 THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 

 COLLEGE.— No. 264. 



ON THE DEVELOPMENT OF THE CORAL AGARICIA 

 FRAGILIS DANA.i 



By J. W. Mayor. 

 Presented by E. L. Mark. Received June 15, 1915. 



CONTENTS 



Page. 

 Introduction 486 



Part I. On the larval development 487 



1 . General considerations 487 



a. Breeding season 487 



b. Extrusion of the larvae 487 



c. Form of the larva 487 



d. Fixation 488 



2. Anatomv 489 



a. Material, methods and general features 489 



b. Description of the mesenteries, mesenterial filaments and gas- 



trovascular cavities of the larvae studied . 492 



Group I. Larva A 492 



II. Larva B 493 



" " Larva C 494 



" Larva D 495 



" Larva E 496 



" III. Larva F 497 



Larva G 499 



Larva H 500 



" IV. Larva I 501 



c. Conclusions as to the course of development of mesenteries, etc. 504 

 Part II. On the postlarval development 506 



1. Form of the young polyp 506 



2. The early development of the skeleton 506 



a. Description of skeleton A 506 



b. Description of skeleton B 508 



c. Conclusions on the early development of the skeleton .... 508 



d. Stage with twelve primary septa 509 



3. Comparison of the development of the skeleton in Agaricia fragilis 

 with that in other Hexacorallidae 509 



Bibliography 510 



Description of plates 511 



1 Contributions from the Bermuda Biological Station for Research. No. 38. 



