€ainpanularian Hydroid {Campanularia Sp.) 



Mateinal. — The student should examine both living 

 and alcoholic specimens. The former, however, can be 

 obtained only by students who live not more than a 

 day's journey from the coast. Pieces of rock-weed, 

 various sea-weeds, eel-grass, bark, shells, etc., bearing 

 specimens may be packed for shipment in a ventilated 

 box with plenty of damp sea-weed. On arrival at their 

 destination the specimens should be placed at once in 

 carefully prepared artificial sea-water or in well-aerated 

 natural sea-water, which may be shipped in casks. The 

 hydroids may be kept alive long enough to give the 

 student some idea of their appearance and motions. 



The structure is best studied in preserved specimens, 

 and these are made by plunging as quickly as possible, 

 so as to avoid contraction of the tentacles, the living 

 hydroids into Perenyi's fluid, and leaving them for 

 three to four hours, or in Kleinenberg's picro-sulphuric 

 acid for the same length of time, then placing them 

 in seventy per cent, alcohol for about twelve hours, 

 and in eighty-five per cent, and ninety-five per cent, al- 

 cohol, each for the same length of time. Some of the 

 preserved material should be stained in hsematoxylin, 

 borax carmine, alcoholic carminic acid, etc., and mount- 

 ed in Canada balsam. The rest may be left unstained 

 and used for both macroscopic and microscopic exam- 

 ination. 



