Page:Proceedings of the Royal Society of London Vol 60.djvu/250

Rh Fxa. 4.—L. Antero-lateral. 1432 Individuals (see fig. 2)

The critical function 2/32—3/3i—6 = 0*306116 is positive, and so the range is unlimited, as was the case with the total and frontal breadths. Using Professor Pearson’s skew curve of unlimited range, and putting x — a tan 6, we have y = y0cos2m 0e~vd, where y0 = 152-4817. v = 4*550107. m = 22*123325. a = 19291468.

The distance of axis y from centroid = 2*077756, and the distance of maximum ordinate from centroid = 0*093918. Both this and the normal curve are drawn, and there is but very little difference between them, the areal deviations being 7*5 and 7*9 per cent, respectively.

R. Dentary Margin.—The mean has a range of about 3^ units, and it rises as the crab grows. The total range of deviation = 436—539 thousandths. As in the other cases, groups 6—12 were selected, and a frequency curve drawn ; the range is 436—531 thousandths, giving 24 units.