Abstract
1. 104 immature individuals (11.4-18.0cm in body length) of Ophiocephalus argus CANTOR (Ophiocephalidae, Teleostei) obtained from Lake Ezu near Kumamoto were examined for the purpose of knowing the relation of the rates of increase of the brain weight, of the body length and of the body weight.
2. The rates of increase of the body weight is larger than that of the body length.
3. The rate of increase of the brain weight is larger than that of the body length.
4. The rate of increase of the brain weight is smaller than that of the body weight.
5. If we apply the formula “Y=ax3” to the relation between the body weight (Y) and the body length (X) then the constant value (a) is calculated to be 0.0147 in male, 0.0148 in female.
6. When the relations among the brain weight (W), the body weight (Y) and the body length (X) are represented by the formula “W=log X×√Y×C” the constant value (C) is generally shown by 0.0277 in male, 0.0275 in female.
7. The increase rates of the brain weight, of the body length and of body weight show the sexual difference, being higher in male than in female.
