APP,] MAMMALIAN SEGMENTING OVA. 461 



freely in the early spring months of the year and will 

 give ample opportunity for the student to observe the 

 exact time when the female is covered. A number 

 of does should be kept together in a large pen, and 

 two or three bucks in separate small cages also placed 

 within the pen ; at the period of heat, the doe should 

 be temporarily placed with the buck and the exact 

 time of copulation noted, the age of the embryo 

 beiug calculated from that hour. 



XII. Examination of segmenting ova. 



It will be well to mention here that although 

 a doe may have been satisfactorily covered, embryos 

 are not always obtained from her. A superficial 

 examination of the ovaries will determine whether or 

 no fertilized ova are present. If ova have been 

 recently dehisced from the ovary, the Graafian follicles 

 from which they were discharged will be found to be 

 of a distinctly red colour. In case no such ' corpora 

 lutea' as they are called are present farther search is 

 useless. 



A. To obtain ova from i to 60 hours old. 



Cut open the abdomen from pubis to sternum, 

 and from the pubis round the thigh of each side, and 

 turn back the flaps of the body wall so formed. 

 Remove the viscera and observe below (dorsal) the 

 single median vagina, from the anterior end of which 

 the uterine horns diverge. 



Observe at the anterior end of each uterine hox'n 

 a small much coiled tube, the oviduct (Fallopian 

 tube) near the anterior end of which a little below 

 the kidney lies the ovary. Cut out the uterus and 

 oviduct together and lay them in a small dissecting 



