The Ecology of Young Tadpoles, with Special Reference to Carbohydrate Changes in Development, and to the Function of the Envelope


  • R. Maxwell Savage B.A., F.I.C., F.Z.S.


  • 1 Comparisons have been made between the final quantities of total carbohydrate in young tadpoles, just before they commence to feed, which have been left on the jelly envelopes, removed into plain water, or placed on a number of artificial media containing carbohydrates. There are no significant differences.
  • 2 Microscopical comparisons have been made on tadpoles from the same batches. No differences have been found.
  • 3 Batches of eggs from four species have been followed day by day all through development and the total carbohydrate determined. It is found that all show similar features: an initial period with only small changes, but a tendency for an increase to take place in the first few days; a sharp drop just about hatching time; and, finally, a period to the end of embryonic development in which there are only very slight changes.
  • 4 Nutrition is not a function of the envelope.
  • 5 It is suggested that the envelope is a heat storage device.