504 



LIFE : OUTLINES OF GENERAL BIOLOGY 



of katabolism. That is to say, the ratio A:K in the female is funda- 

 mentally greater than the ratio a.kin a. male of the same weight. It is 

 not, of course, inconsistent with this that there should be, as there 

 often is, a difference in the chromosomes of the nucleus in the two 

 sexes. The chromosomal difference may be an index of a physio- 

 logical or biochemical difference which goes deeper. It should 

 never be forgotten that one and the same animal may change its 

 sex in the course of its lifetime, and sometimes does so normally 

 — a fact which is distinctly in favour of the physiological inter- 

 pretation. 



But what we are concerned with at present is the suggestion 



Fig. 



74- 



The Transformed Hectocotylus Arm of a Male Cuttlefish. ST, the base of 

 the arm; SU, double rows of suckers; H, hook; F, terminal filament. 



made by Riddle and Reinhart that the Manoilov reaction is a better 

 indicator of metabolic rate than of .sex, and that the reason why it 

 often works correctly in determining the sex from the blood or the 

 extract is to be found in the radical relation between metabolism 

 and .sex. "The numerous studies that have been made on plants and 

 animals with the Manoilov test have notably extended the evidence 

 for the metabolic theory of sex." 



PARASITIC MALES.— Mr. Tate Regan, Director of the British 



Museum, has described one of the most extraordinary sex-relation- 

 ships in the whole animal kingdom — and that is saying a good deal. 

 In three different kinds of deep-water Angler-fishes, two of them 

 new to science, he found that the female was carrying about a 



