Page:Popular Science Monthly Volume 62.djvu/56

50 though worked out into the minutest details, is wholly artificial and arbitrary; yet the exact correspondence of the areas with the patterned mounds of the monkey palm show that we are dealing here with definite morphological parts, and the variations that occur are caused by reduction, hypertrophy, fusions, separations and other principles with which the morphologist is familiar.

Thus, considering the three palmar areas alone, they will be found either all distinct (Fig. 6, a and b) or two of them may be confluent (Fig. 6, c, P2 and P3), or semi-confluent (Fig. 6, d, P1 and P3). They may be open, i. e., may extend to the margin (Fig. 6, b, P1 and P2) or closed (Fig. 6, c, P2 and P3). Semi-confluent areas may also be termed

divided, since this condition is brought about by the division of one of the areas by a primary line, and in the same way a single closed area (Fig. 6, b, P3) may be termed circumscribed, since this condition is brought about by the fusion of the two primary lines which serve as boundaries.

In size an area may vary between a very large one (Fig. 6, b, P1} and a greatly reduced one (Fig. 6, d, P2), and in the latter case the reduction may become so extreme as to end in the complete loss of an area, a condition which would be obtained if we should consider the second and third palmar tri-radii of Fig. 6, d, which are here very near