We have yet to trace the shorter of the two bands which originate in the splitting of the middle mass of fibres, cac, in fig. 278, to embrace the right ventricle. This view ex hibits only the inner fibres of this mass as they are prolonged into the inner or longer of the two bands; but fig. 28i affords an outer view of this mass of fibres as they are prolonged into the outer or shorter band. They are seen winding spirally up from the apex marked cac, and at the anterior coronary track, act, they split, in the form of a band, from the general mass to pass over the lower half of the cavity of the right ventricle. In this figure this band is separated and left extended, in order that the accessions of fibres it receives from the right surface of the septum may be seen, which are the fibres A from the aorta AA, and the fibres c and c form two of the carnew columns: (not in view) passing obliquely down from right to left to the anterior edge of the septum, from which they extend into the band which is lettered CAcc, and unite in timately with its fibres. When the band is replaced in its course over the ventricle, its accessory fibres are made to reflect at an acute angle upon themselves, and thus form the apicial part of its anterior boundary. This
band describes one spiral circle round the heart, arriving again at the anterior coronary track at its basial extremity ; it is inserted into the aorta, and if the fibres make a very oblique approach to the base, they will be also inserted into the tendinous margin of the annulus arte riosus. The continuation of this band round the posterior side of the heart can be traced in fig. 279. Its width is equal to about a third of the heart's axis ; it is seen marked CAcc in its spiral ascent from left to right, passing, first, a little below the middle third of the heart ; at the posterior coronary track, pct, becom ing the middle third, and afterwards approach ing gradually the base in its way to its points of insertion before-mentioned.
As the tracing the fibres from the circum ference to the centre, and from the centre to the circumference, is a matter of much difficulty, and as the description has hcen attended with much detail, it is desirable that a more general and concise view by means of a diagram should be afforded of the courses which the fibres take in constructing this organ.