NATURAL HISTORY, 219 



§ V. EMBRYOS. 



Much of the future ])ro<^resa of zoology will depend upon the extent 

 and variety of the collections which may he made of the emhryos and 

 foetuses of animals. No opportunity should be omitted to procure 

 these and preserve them in spirits. All stages of development are 

 equally interesting, and complete series for the same species would be 

 of the highest importance. Whenever any female mammal is killed, 

 the uterus should be examined for embryos. Wiien eggs of birds, 

 reptiles, or fish are emptied of their young, these should be preserved. 

 It will be sufficiently evident that groat care is required to label the 

 specimens, as in most cases it will be impossible to determine the 

 species from the zoological characters. 



§ VI. NESTS AND EGGS. 



Nothing forms a more attractive feature in a museum, oris more 

 acceptable to amateurs, than the nests and eggs of birds. These 

 should be collected whenever they are met with, and in any amount 

 procurable for each species, as they are always in demand for purposes 

 of exchange. Hundreds of eggs of any species with their nests (or 

 without, when not to be had) will be gladly received. 



Nests require little preparation beyond packing so as to be secure 

 from crumbling or injury. The eggs of each nest, when emptied, 

 may be replaced in it and the remaining space filled with cotton. 



Eggs, when fresh, and before the chick has formed, may be emptied 

 by making a small pin-hole at each end, and blowing or sucking out 

 the contents. Should hatching have already commenced, an aperture 

 may be made in one side by carefully pricking with a fine needle 

 round a small circle or ellipse, and thus cutting out a piece. The 

 larger kinds should be well washed inside, and all allowed to dry be- 

 fore packing away. If the egg be too small ior the name, a number 

 should be marked with ink corresponding to a memorandum list. 

 Little precaution is required in packing, beyond arranging in layers- 

 with cotton and having the box entirely filled. 



The eggs of reptiles, provided with a calcareous shell, can be pre- 

 pared in a similar way. 



The eggs of fishes, salamanders, and frogs may be preserved in 

 spirits, and kept in small vials or bottles. A label should never be 

 omitted. 



§ VII. SKELETONIZING. 



Skulls of animals may be prepared by boiling in water for a few 

 hours. A little potash or lye added will facilitate the removal of 

 the flesh. 



Skeletons may he roughly prepared by skinning the animal and 

 removing all the viscera, together with as much of the fle^^h as possi- 

 .ble. The bones should then be exposed to the sun or air until com- 

 pletely dried. Previously, however, the brain of large animals should 

 be removed by separating the skull Irom the spine, and extracting 



