THE A ME RICA N NA TURA LIS T. [Vol. XXXVII. 



Methods. — The specimens at my disposal were collected by 

 Dr. C. W. Hargitt at Wood's Holl, Mass., during the summer 

 of 1900. Several methods of killing and preserving were used. 

 My best results were obtained from material killed in corrosive 

 acetic acid. Formalin and Flemming's solution gave less satis- 

 factory results. 



In the study of general histological features I found that in 

 toto staining in' borax carmine was both a satisfactory and conven- 

 ient method. Specimens might be left in the stain from 10 to 

 48 hours and then the stain extracted to any desired degree in 

 1 ' J arid-alcohol. Dehydration required from one to two hours. 

 For clearing, cedar oil, clove oil, xylol or turpentine were used; 

 xylol or turpentine proving most satisfactory. 



In the study of the developmental features a number of sec- 

 tions were stained on the slide with iron-hamiatoxylin. Combi- 

 nations of iron-haematoxylin and Bordeaux red, and of eosin and 

 haematoxylin were used with good success. 



In the former combination sections were placed in a 2% solu- 

 tion of ammonio-ferric-alum for from thirty minutes to four hours. 

 After this they were washed for several minutes in running 

 water and then stained in a 5 % aqueous solution of haematoxylin 



was obtained. After rinsing the sections in water they were 

 stained from fifteen minutes to one half hour in Bordeaux red, 

 carried up through the alcohols and mounted in balsam. 



In the eosin-hasmatoxylin method sections were first stained 

 from one to two hours in a 2 % solution of alcoholic eosin and 

 then from five to fifteen minutes in a weak solution of Delafield's 



first things that was called to my attention in taking up the 

 study of the morphology of Corymorplia pcndnla, was the presence 

 of a smaller hydroid associated with it. These smaller forms have 

 all the appearance of true buds. In some cases they are found 

 attached to the hydrocaulis, and in others they are observed 

 springing up from within the tangled network of rhizoidal fila- 



