OCR Text |
Show 494 PIvOF. W. H. FLOWER ON THE [Nov. 1 I, of muscular fibres from the rectum pass over this sac and are inserted into the skin above it. Circular fibres pass around it, enclosing the follicle and anus in a common sphincter. O n making a section through the thick wall of this sac, it is seen to be composed of a number of pyramidal dark-coloured glandular bodies, with the broad ends at the outer surface, and their apices towards the inner wall of the follicle, and separated from each other by a thin layer of areolar tissue. Within the apical portion of each gland is an oval cavity containing a yellowish cheesy substance. Each of these little reservoirs communicates with the large sac by one of the minute round orifices previously noticed. Fig. 11. Termination of rectum and anal glands, from above; natural size. B. Superior surface of rectum. F. Supraanal follicle. G. Lateral glandular sacs. On each side of this median supraanal gland, and lying on the outer and upper surface of the rectum, is a conspicuous body (fig. 11, G) of a somewhat oval shape, 1*6" in length, and 1" wide at its thickest part. W h e n cleaned from the investing lax cellular tissue and a not very distinct layer of muscular fibres, it is seen to be smaller at the upper and anterior end, broad at the posterior end (where it comes into contact with the skin), convex externally, and flattened or slightly concave on the surface which lies against the outer wall of the rectum. It is attached only by a very short pedicle *2" wide, which connects it with the lateral part of the supra- |