PHORONIS ARCHITECT.*: ITS LIFE HISTORY, ANATOMY, AND 



BREEDING HABITS. 



INTRODUCTION. 



The study of Phoronis wrchitecta was begun in the summer of 1901 and continued in the 

 summer of 1902 at Beaufort. N. C. We are indebted to the Hon. G. M. Bowers, United States 

 Commissioner of Fisheries, for the privilege of working in the Commission's station at Beaufort, 

 where all the conveniences necessary for scientific investigation are at hand: to Prof. H. V. 

 Wilson, director of the station in 1901, and to Dr. Caswell Grave, director during L902, for 

 many kindnesses. 



While the study of the live material was for the most part done at Beaufort, the rest of the 

 work was pursued in the zoological laboratory of the Johns Hopkins University. 



Since the discovery of Phoronis hippocrepia by Wright in L856, the affinities of this inter- 

 esting genus have been more or less under discussion. Different investigators have sought to 

 ally the Phoronidse with the Bryozoa, the Brachiopoda, the Sipunculida, and other groups. 



Roule (1*0) thinks that the Phoronidas should be placed next to the Bryozoa in a natural classi- 

 fication. He does not consider that they have any affinity to the Entt mjpm usta, but from a study 

 of the early stages of development he finds that they are related to the true Chordata (tunicates 

 and vertebrates). He says. "16mbryon de Vertebre est une Trochophore renversee." 



Lankester and Mcintosh are inclined to consider Phoronis, < 'ephalodiscus, and Rhabdopleura 

 as related forms, while Harmer (7) makes a comparison of Phoronis with Oephalodiseus and 

 thinks that perhaps there may be some affinity. 



Masterman (1."). 16) in a series of papers made a comparison of the actinotrocha larva of 

 Phoronis with Balanoglossus and its larva and also with Cephalodisous. In this paper, he arrives 

 at the conclusion that there is a close genetic relationship between the Phoronida>, Balanoglossus, 

 and Oephalodiseus. Since the appearance of Masterman's papers, Ikeda (9) has investigated the 

 develdpment of Phoronis ijimai and has made a careful study of several Actinotrochse found in 

 Japanese waters. Shortly after this, Longchamps (12) published a comparative study of the 

 early development of several species of Phoronis and also of several species of Acti/notrochse, 

 giving a very careful critical resume of the work done by different investigators. 



Menon (17) has lately published a short paper on the Actinotrochse, in which he considers 

 the Phoronidse to be related to the Chordata, but thinks the relationship is to be traced through 

 a form like Rimini,, pi, urn. 



This study of the development and anatomy of Phoronis architecta was begun before the 

 publication of the last four papers mentioned, and when they appeared the abandonment of this 

 investigation was seriously considered. However, since there seem to lie specific differences and 

 since there are several disputed points in the development, it seems best to publish the results of 

 this study. 



It is hardly necessary lo enter into an historical account of the work that has been done on 

 the development and anatomy of the Phoronidse, since there are several papers which have 

 reviewed the subject exhaustively. 



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