CO 



388 PREPARATION OF BIRD SPECIMENS 



Determination of sex. — The sex of the specimens should be 

 determined by dissection. The sexual organs are situated be- 

 tween the intestines and the backbone at about the middle of 

 the body, but somewhat on the left side. These organs are 

 large and easily recognized in the spring. The male organs 

 (the testes) are two in number, light, yellowish-white in color, 

 somewhat elongated in form, and, in the English sparrow, in 

 spring, about the size of large peas.^ The female organs (the 

 ovaries) are clusters of different sized, globular, grape- 

 like parts, united together in a membrane.^ The 

 English sparrow is a good species to learn from, 

 because the plumage of the head and neck enables one 

 to distinguish the sex before dissection. The best 

 place to cut the body open is along the left side ; then 

 by lifting the intestines the sexual organs can be seen. 

 By beginning in the spring and opening a sparrow of each sex 

 each month throughout the year a better knowledge of these 

 organs will be obtained, and an easier recognition of them in all 

 conditions than by any amount of description or illustration. 



Cleaning eggs. Instruments, etc., needed. — Two or three egg 

 drills of different sizes ; two or three blow-pipes of different 

 sizes ; a very slender pair of scissors made for the purpose ; 

 light spring forceps ; a hook formed of a bent needle mounted 

 in a handle ; a basin of water ; some cotton. The proper instru- 

 ments can be obtained from any of the dealers in naturalists' 

 supplies. 



If the egg is fresh a small hole, a little larger than the point 

 of the smallest blow-pipe, should be carefully drilled in the side. 

 Introduce the blow-pipe about a sixteenth of an inch, and blow 

 gently and steadily till the contents are removed. Fill the 

 mouth with water and blow this into and out from the egg so 

 as to rinse it thoroughly. Place the egg with the hole down- 

 ward on some cotton to dry. 



If the egg contains an embryo it will be necessary to drill 

 a larger hole in the side so that the hook, scissors, and forceps 

 can be used as they are needed. Afterwards thoroughly rinse 



