. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. THE LENGTH/WEIGHT RELATIONSHIP 303 Zemskiy (19506, figs. 2, 3) demonstrated this by means of detailed measurements of sixty-six fin whale embryos between 49-5 and 569 cm. in length. He took five series of measurements (snout- umbilicus ; snout-anus; head length; pectoral girth; anal girth) and showed that the ratio of these measurements to body length (expressed as percentages) remained more or less constant within this range of foetal lengths. The smaller series of foetal measurements given by
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. THE LENGTH/WEIGHT RELATIONSHIP 303 Zemskiy (19506, figs. 2, 3) demonstrated this by means of detailed measurements of sixty-six fin whale embryos between 49-5 and 569 cm. in length. He took five series of measurements (snout- umbilicus ; snout-anus; head length; pectoral girth; anal girth) and showed that the ratio of these measurements to body length (expressed as percentages) remained more or less constant within this range of foetal lengths. The smaller series of foetal measurements given by Mackintosh and Wheeler (1929, pp. 324-29) are in very close agreement. These authors also give the results of similar measure- ments on over 600 post-natal fin whales. Their mean percentage values for these three linear proportions in adults are very close to the mean values for foetuses and well within the foetal ranges. Zemskiy states that the throat grooves (a special feature of the rorquals) first become apparent at a length of i-o m., and become distinct and similar in appearance to those of the adult at a length of 1-5 m. The baleen is first discernible externally in embryos of about 3-o-4-o m. (Mackintosh and Wheeler, 1929, fig. 96; Zemskiy, 1950). 10,000. LENGTH IN METRES Text-fig. 13. Plot of foetal weight against length for 234 blue, fin and sei whales (black circles), nine humpback whales (white circles), and ninety-three porpoises (crosses = monthly mean values). Regression lines have been fitted by eye and the neonatal values for blue, fin and humpback whales are indicated. In the last 5 months of pregnancy the blue whale foetus grows in length from 1-3 to 7-0 m., corre- sponding to an increase in weight of 2480 kg. (from 20 to 2500 kg.) or 2-44 tons. In the last two months of pregnancy the average gain in weight is over 2 tons (420-2500 kg). The gro\vth rate of the fin whale is of the same order of magnitude. In some individual blue whales the growth rate is prob-
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