480 MISSES K. FOOT AND E. C. STKOBELL : 



the male possessing certain organs of sense or locomotion, of wliicli the 

 female is quite destitute, or in having them more highly developed, in order 

 that he may readily find or reach her; or again, in the male having special 

 organs of prehension so as to hold her securely. These latter organs of 

 infinitely diversified kinds graduate into, and in some cases can hardly be 

 distinguished from^ those which are commonly ranked as primary, such as 

 the complex appendages at the apex o£ the abdomen in male insects. Unless 

 indeed we confine the term ' primary "" to the reproductive glands, it is 

 scarcely possible to decide, as far as the organs of prehension are concerned, 

 which ought to be called primary and which secondary '■" (p. 253). 



Morgan (M3) also appears to accept Hunter's classification, for in his 

 rather full list of secondary sexual characters he includes none that are 

 " directly connected with the act of reproduction.'^ He opens his discussion 

 of secondary sexual characters as follows : — 



" The Secondary Sexual Characters. 



" In the most highly evolved stages in the evolution of sex a new kind of 

 character makes its appearance. This is the secondary sexual character. In 

 most cases such characters are more elaborate in the male, but occasionally 

 in the female. They are the most astonishing thing that nature has done : 

 brilliant colours, plumes, combs, wattles, and spurs^ scent-glands (pleasant 

 and unpleasant) ; red spots, yellow spots, green spots, topknots and tails, 

 horns, lanterns for the dark, songs, bowlings, dances and tourneys — a medley 

 of odds and ends" (p. 2^). 



If we are to discard Hunter's classification, because it is found dilficult to 

 determine to which class some of the characters rightly belong, we should 

 have to be dissatisfied with many classifications that are thoroughly well 

 established. 



If we limit the term " primary sexual characters " to the reproductive 

 glands, it offers an escape from the difficulties in classifying the prehensile 

 organs, as Darwin has pointed out; but it would seem that greater difficulties 

 are met by refusing to ])lace the intromittent organ in the same group with 

 the reproductive glands, and placing it in the group with characters so far 

 removed from " direct connection with the act of reproduction ", as, lor 

 example, Morgan's list of secondary sexual characters. The intromittent 

 organ is not only " directly connected with the act of reproduction ", bat it 

 is as much a part of the sex of the individual as the reproductive glands 

 themselves. Any one of the characters in Morgan^s entire list of male 

 secondary sexual characters could appear in the female without changing 

 her sex; but the intromittent organ is as clearly indicative of the sex as are 

 the reproductive glands themselves. 



If a definite chromosome carries the factors for determining sex, and it 

 therefore carries the factors for the reproductive glands, it would seem 

 logical to suppose that the chromosome carrying the factors necessary for 



