MICROSCOPIC OBJECTS. 49 



mal producing an offspring, which at no time resembles 

 its parent, but which, on the other hand, itself brings 

 forth a progeny, which returns in its form and nature to 

 the parent animal, so that the maternal animal does not 

 meet with its resemblance in its own brood, but in its 

 descendants of the second, third or fourth degree or 

 generation ; and this always takes place in the different 

 animals which exhibit the phenomenon, in a determinate 

 generation or with the intervention of a determinate num- 

 ber of generations." As examples of this mode of 

 development, Steenstrup adduces the Medusae ; certain 

 Zoophytes, as the genera Coryne, Campanularia, &c. ; 

 the cychcal development of the Vorticellee among In- 

 fusoria, and of the Aphides among Insects. 



Leg of Bee with nectar. — If a Bee be caught immedi- 

 ately after it has been gathering the nectar from some 

 flowers, and the inner side of the legs be examined, they 

 will be found laden with the material on which the insects 

 feed, and from which they elaborate the wax and honey. 

 The leg is best examined when mounted on a half- inch 

 black disc, with a power of 30 diameters. (Note. — This 

 object should not be put away with others, as the vegeta- 

 ble matter is liable to mildew or to invite small acari to 

 feed upon it.) 



Muscular Fibre. — ^The important functions of the mus- 

 cles in the animal economy — ^whether we consider their 

 powerful and incessant action in the heart, their strength 

 in the legs, or the wonderful and varied effects produced 

 by their energy in the hand — render their modus operandi 



