also the size of the crab 12 must be taken into consideration when dimensioning the space between the platform 18 and the top shell 16 through which the crabs 12 must be able to fit further it is proposed to provide an air bubble within the chamber 30 which will only partially deplete after a significant period of time thus the respiration rate of the crab must be taken into account to determine an appropriate size for a habitat 10 it is first of all to be understood that an adult crab 12 of the species uca minax may be maintained by the oxygen in one cubic inch of air over a period of one and one half days thus it is desired to provide the chamber 30 with a minimum volume of 19 5 cubic inches to provide a thirty day supply of oxygen for one crab 12 this is not to say that one should wait the full 30 days to replenish the air within the chamber 30 the crab 12 will by decrease of activity level or by leaving of the habitat 10 indicate that a replenishment is necessary to accommodate the size of the crab 12 as well as air supply requirements it is preferred to create a chamber 30 for a single crab 12 having dimensions of approximately 3 u00d7 3 u00d7 2 5 inches with respect to.