agree on many important points, still on others, notably the 

 origin of the nervous system, they stand at the greatest va- 

 riance. 



While the llarine Laboratory of the Johns Hopkins 

 University was stationed at Beaufort, N. C, during the sum- 

 mer of 1H94, I collected material for the purpose of studying 

 the development of the buds of Perophora viridis , Verrill, 

 which was found there in great abundance. This material I 

 supplemented the follov/ing summer at V/oods Holl, Mass. while 

 working in the laboratory of the United States Pish Commis- 

 sion. 



My main object in undertaking the investigation was 

 to compare the bud -development of Perophora with that of Bo- 

 tryllus, as described by Hjort (8), and especially to deter- 

 mine, if possible, the origin of the nervous system. 



The material, which was easily obtained at both 

 places in large quantities, proved to be most excellent for 

 my purpose, as it contained an unlimited supply of buds in 

 all stages of development. 



The preserving fluids used were, 1, glacial acetic 

 acid; 2, a mixture of eighty parts concentrated corrosive 

 sublimate solution and twenty parts glacial acetic acid; and 

 3, Perenyi's fluid. The latter reagent gave perhaps the 

 most satisfactory results, although very good preparations 

 were obtained with the sublimate-acetic mixture, when the ob- 

 jects were left in it not longer than ten minutes. 



Mayer's Haemalum proved to be most serviceable. 



