xi PRACTICAL DIRECTIONS 549 



care to preserve the natural relations of the parts. Dissect 

 away all the superfluous connective -tissue and fat, separate 

 the rectum at its cut end from the urinogenital canal, and 

 turn it on one side, noting the rectal and perinea! glands. 

 Make out, in addition to the parts referred to in VIII : 



A. In the male. The uterus masculinus and prostate, and 

 the sperniiducts passing between the former and the bladder. 



Sketch the entire dissection. Then slit open the uterus 

 mascuiinus so as to see the openings of the spermiducts, 

 remove the rectum and rectal glands, and make out the 

 relations of the corpus spongiosum. Make a median incision 

 along the whole length of the penis, beginning at the apex 

 and cutting through the fibrous septum between the two 

 corpora cavernosa : continue the incision forwards, so as 

 to open the bladder along its ventral wall, and note and 

 indicate on your sketch the openings of the ureters into the 

 bladder, and the crescentic aperture of the uterus mascu- 

 linus into the urinogenital canal, just at the anterior edge of 

 a cushion -like fold. 



B. In the female. The wide urinogenifal cana 1 with its 

 vascular walls. 



Sketch the entire dissection. 



Make a median longitudinal incision through the urino- 

 genital canal, and continue it forwards until the cavity of 

 the bladder is exposed : slit open the vagina and one of the 

 uteri and uterine tubes in the same way. Xote and indicate 

 on your sketch the openings of the ureters into the bladder, 

 the connection of the neck of the bladder with the urino- 

 genital canal, the large aperture in the latter leading into 

 the vagina, and the thick-lipped aperture (os uteri) communi- 

 cating between the vagina and thick-walled uterus, between 

 which and its fellow is a vestigial septum, indicating the 

 primarily paired character of the vagina. Insert a seeker 

 in the ccelomic aperture of the uterine tube. If your speci- 

 men is in an early stage of pregnancy, young embryo 

 (blastocysts, p. 586) may be present in the uterine tubes, and 

 should be carefully removed and fixed in corrosive sublimate 

 (p. 136) : if the uteri contains later embryos they present a 

 series of swellings : cut one of the swellings open from the 

 ventral side, and note the foetus, enclosed by the amnion 

 (p. 606), and attached to a discoid placenta (p. 610) ; cut 

 out the other swellings, together with their contents, and 

 preserve them in formaline or alcohol. Microscopic sections 

 of the ovary should be examined, and the hollow ovisacs 

 noted, each consisting of follicular cells enclosing a minute 

 ovum. 



