PARTS OF INSECTS, AND MISCELLANEOUS OBJECTS. 143 



FUSCHIA. In figure 245, several particles of the po'len of the fuschia are 

 displayed, magnified one hundred and ten times. F\. 245. 



They are of a brown color, and are similar in shape 

 to the pollen of corn when viewed, as they are dif- 

 fusely spread in their natural state over the surface of 

 a slip of glass. But when they are immersed in a 

 layer of balsam between two plates of glass, thev as- 

 sume a different form, and little round appendages are 

 then distinctly discerned like handles, at each corner, as 

 exhibited in the figure. One of the largest of these 

 specimens measures in its longest extent, the three hun- 

 dred and sixtieth part of an inch. 



fig. 246. 



SWEET PEA. The pollen of the sweet pea is delinea- ^. 



ted in cut 246, as it is revealed under a considera- |l 



ble magnifying power. It appears as a collection of ^^ V A 

 brown oval grains, with central cells of the same shape, 

 placed lengthwise of the grains, and their positions are in- 

 dicated by the light lines in the several figures : the clear 

 fluid with which the cells are filled, rendering them trans- 

 parent. The length of one of these atoms is the jive r A 



hundredth part of an inch, and the breadth one-six hun~ " 



dred and twenty-fifth part. 



FERN SEED. The seed of the fern affords an interesting object for the mi- 

 croscope, and in cut 247 a sketch of various parts of the plant is presented, 

 which is taken from Swammerdam. a represents a stalk of fern, the leaflets of 

 which at the lower part of the stem are thickly covered upon the back with the 

 seed-vessels of the plant. At 6 and c, two of these seed-vessels are seen highly 

 magnified. The stalk of the seed-vessel is smooth, but where it unites with the 

 pods it changes into a strong cross-ribbed thread, which completely encircles the 

 pod and holds it firmly together. This singular cord is shown at i, as it ap- 

 pears edgewise, and in c, a side view is presented, with the enclosed pod, the 

 shaded line across the latter indicating the position of a natural fissure in the 

 pod. When the seed is ripe, the circular elastic cord is straightened out, and in 

 tho process of unbending, opens the seed-vessel, completely separating it into 

 two parts through the natural fissure, and forming two hemispherical cups, which 

 are attached by short stems to the elastic cord. This stage of development is 

 seen at c?, where the straightened cord and the two open hemispherical cups are 

 delineated. By imagining the elastic cord to be bent back into its original shape, 

 it is evident that the edges of the two cups would unite, and that the figure d 

 would re-assume its original form as shown at c. At e a seed-vessel is shown, 

 in which an opening has been made, and a portion of the enclosing membrane 



