[Increase functions of the type dW/dt=k Wm/(t + to)p and their integrals (author's transl)].

The testing of a dozen functions for the length of the Alaskan razor clam Siliqua Patula (Bivalvia) by the author (Sager 1980) has given the best results when applying the increase ansatz dW/dt=k Wm/tp proposed after a series of investigations into mathematical properties of organic growth (Sager 1979a). The resulting growth function is restricted to vanishing values of the birth length however as is practically the case with the razor clam measuring 0,01 cm at birth and reaching 15 to 16 cm after at least 12 years of age. When the quotient of initial and final length or weight will go up with changing to other species in future investigations, the increase function must be extended to dW/dt=k Wm/(t + to)p, giving quite different solutions for m = 1 and 0 < m < infinity but m not equal to 1 respectively. The properties of the growth functions are discussed, and the evaluation of the parameters shown putting speical attention to the influence of to.