102 BULLETIN OF THE 



following summer, I gathered most of the material for this study. I 

 found an excellent place for collection in Fresh Pond, Falmouth, where 

 Fredericella and Plumatella were also gathered. Upon my first visit to 

 this pond (July 5th), I found at its outlet Cristatella exceedingly abun- 

 dant on the leaves of the pond-lilies. A month later, the same locality 

 yielded very few specimens ; but about September 5th I found them 

 plentiful again, and at the same time noticed the phenomenon described 

 by Kraepelin and by Braem, — that some of the statoblasts of Pluma- 

 tella had already hatched. Colonies of from five to twenty individuals 

 were observed with the two halves of the statoblast still adhering to 

 their bases. A few colonies of Cristatella were also gathered in the 

 latter part of August from Trinity Lake, New York. 



The material collected was killed with a variety of reagents. Cold 

 corrosive sublimate gave the best results. In staining, I always found 

 Czoker's cochineal the most satisfactory dye for the study of the 

 embryonic cells of the bud. 



As Haddon ('83, pp. 539-546) has reviewed the most important part 

 of the bibliography of budding in Phylactolsemata which had been 

 published at the time of his writing, I shall be relieved from giving 

 here any extended historical account of the earlier researches. The 

 contributions of Nitsche ('75) and Hatschek ('77) are well known. 

 Reinhard has published a preliminary article ('80% '80 b ) on this subject 

 in the Zoologischer Anzeiger ; but his two more important papers 

 ('82 and '88) I have unfortunately not seen. Braem's ('88, '89 a , and 

 '89 b ) three preliminary papers concerning budding in fresh- water Bry- 

 ozoa correct some erroneous statements of Nitsche, and support Hat- 

 schek's view of the origin of the polypide. The results at which I 

 have arrived concerning this last problem are similar to those of 

 Braem, but his work has apparently been done chiefly on Alcyonella. 

 mine on Cristatella. Finally, I believe there will be found in this paper 

 something new on the organogeny, which Braem does not seem to have 

 especially studied, and which may be of general morphological impor- 

 tance. For these reasons, it has seemed to me desirable that I should 

 publish my observations and conclusions, and I am the more inclined 

 to do so because our views are not in all points the same. 



In the matter of nomenclature, my studies have not led me to a final 

 conclusion as to the homologies of the axes of the individual, and there- 

 fore I fall back by preference on non-committal terms. The individual 

 is bilaterally symmetrical. Parts nearer the mouth end of a line joining 

 mouth and anus (i. e. nearer the margin of the colony) will be desig- 



