OCR Text |
Show 238 MR. G. E. DOBSON ON CAPROMYS MELANURUS. T^pr. I, backwards, divides near its insertion into three slips, of which the two superficial (r, r2-r', r 2) interdigitate with those of the muscles of the opposite side, and are inserted into the symphysis pubis on the side opposite to those from which the muscle is derived; the third slip (rs-r'3) passes directly to its insertion into the corresponding side of the symphysis pubis, close to its fellow of the opposite side. The arrangement of the interlacing slips is as follows :-The most superficial slip (r) is derived from the left rectus ; this crosses a slip (r') from the superficial surface of the right rectus and is inserted into the right side of the symphysis pubis, while the latter ("•*') passes to the left side ; the next slip is the second (r2) from the Fig. 2. Semi-diagrammatic, showing the relative portions of the intersecting slips of tbe right and left recti abdominis and of the obliqui externi muscles near their attachments to the pubic bones. left rectus, proceeding to its insertion into the right side of the symphysis under cover of the first slip (r), while the deepest of the interdigitating slips is the second (r'2) from the right rectus, which passes to its insertion into the left side of the symphysis undercover of the first from the same muscle. Obliquus externus, obliquus internus, transversalis.-These muscles present no peculiarities. N o blending together of the obliqui externi with the recti, as described by Prof. O w e n in C. pilorides (P. Z. S. 1832, p. 74) was found in this species ; the internal fibres (o) of the first-named muscles are inserted into the symphysis pubis, under cover of and slightly external to those of the deep interdigitating slips of the recti, as shown in figure 2. Muscles of the Back, Thorax, and Abdomen. Trapezius anticus (fig. 1, t.a) arises from the inner third of the occipital crest, from the centre line of the neck, and from three or four dorsal spines, and is inserted along the spine of the scapula to the end of the acromion, and into the outer third or more of the |