542 



COLLECTION AND MOUNTING OF ZOOPHYTES. 



that express purpose by Mr. Lister, to whom we owe not only 

 many improvements in the Microscope and its appurtenances, but 

 also some of the earliest and best observations upon this class 



of Zoophytes 

 Fig. 277. which the ap- 



plication of the 

 Achromatic 

 principle per- 

 mitted.* In 

 mounting Com- 

 posite Hydro- 

 zoa, as well as 

 Polyzoa, it will 

 be found of 

 great advan- 

 tage to place 

 the specimens 

 alive in the 

 Cells they are 

 permanently 

 to occupy, and. 

 to then add 

 Alcohol drop 

 by drop to the 

 Sea - water ; 

 this has the ef- 

 fect of causing 

 the protrusion 

 of the animals, 

 and of ren- 

 dering their 

 tentacles 

 rigid. The 



Alcoholized 



b, portion li( l uid , ma y 

 be withdrawn, 



and replaced by 



Goadby's Solution, Deane's Gelatine, Glycerine Jelly, Weak Spirit, 

 Diluted Glycerine, a mixture of Spirit and Glycerine with Sea- 

 water, or any other menstruum, by means of the Syringe ; and it 

 is well to mount specimens in several different menstrua, marking 

 the nature and strength of each, as some forms are better pre- 

 served by one and some by another. + The size of the Cell must 

 of course be proportioned to that of the object ; and if it be 

 desired to mount such a specimen as may serve for a characteristic 



* See his Memoir in the " Philosophical Transactions " for 1834. 

 t See Mr. J. W. Morris in " Quart. Journ. of Microsc. Science," N.S. 

 Vol. ii. (1862), p. 116. 



Sertularia cupressina : — a, natural size 

 magnified. 



