142 PRACTICAL MICROSCOPY. 



powers. A section of one of these may be seen delineated 

 in Fig. 107. 



Books which may be consulted: Forbes's ' British Star- 

 Fishes ' ; Agassiz's ' Echinodermata Viv. et Foss.' 



FERNS require no special apparatus for collecting save a 

 sharp knife and a tin collecting box ; they form a very 

 interesting study. The stem may be double stained, as 

 described in the chapter on the staining and injecting of 

 objects. 



How many microscopists are there who possess fern 

 preparations in their cabinet, spores and sori, stems in 

 cross and vertical section, double and single stained, and 

 yet are totally unacquainted with the life-cycle of a single 

 species ; who have looked at sori and spores innumerable, 

 and yet never made the effort of allowing these to ger- 

 minate, and to observe them in their various and strange 

 mutations. 



The Lastrea filix-mas, or male fern, is one of the best 

 species to study for the beginner, and there are many 

 others easily found, such as A thyrium filix-fcemina (lady 

 fern), Scolopendrium vulgare (hart's tongue), Pteris aqui- 

 lina (common bracken),- A diantum capilhis- Veneris (maiden 

 hair), and many others. 



Books which may be consulted : Moore's ' Index Filicum ' ; 

 'Handbook of British Ferns' ; Newman's ' British Ferns ' ; 

 J. Smith's ' Ferns, British and Foreign ' ; Hooker and 

 Baker's ' Synopsis Filicum.' 



FORAMINIFERA. These gelatinous, structureless ani- 

 mals are mostly sought after for the sake of the shells, 

 serving them as a covering. The shells are pierced with 

 holes, through which the animal protrudes its pseudopodia, 

 using them as a means of locomotion. They are found 

 in largest numbers in the sand and mud from the sea- 

 bottom, but may also be found on sea-weeds, and in 



