19,6 Okamoto: Secondary Sexual Characters in Loaches 725 
sue under the dermal layer and in the scale pouches is not ex- 
actly known. I shall investigate this point some time in the 
future. ) 
REFERENCES 
(1) CunnincHaM, J. T. Sexual dimorphism in the animal kingdom. (A 
theory of the evolution of secondary sexual characters.) London 
(1900). 
_ (2) GEDDES and THOMSON. The evolution of sex (1901). 
(8) REGAN, C. T. Sexual differences in the poeciliid fishes of the genus 
Cynolebias. Ann. & Mag. Nat. Hist. VIII 10 (1912) 641. 
1830183——7 
