1904.] MONTGOMERY — MORPHOLOGICAL SUPERIORITY. 371 



nervous system. Phylogenetically the peripheral nervous system, 

 composed essentially of sensory nervous units, is the earlier, more 

 primitive condition ; while the centralized reflex-mechanism is later 

 and morphologically higher. First the simple surface sensory 

 apparatus, later the internal coordinating centre. As the central 

 nervous system becomes more complex, a process denoting morpho- 

 logical advance, the more complex sense organs are apt to disappear 

 or to be replaced by more numerous ones of less complexity. 



It follows from these considerations for the arthropodous groups, 

 that though in a few cases the males may be equipped with sense 

 organs of larger size, this character by no means implies structural 

 superiority, and especially not when it can be shown that with it is 

 associated a less complex central nervous system. Indeed in the 

 ant the male is decidedly inferior, with regard to the nervous system 

 as a whole. 



The other secondary differences, as those of external form and 

 coloration, are generally to the credit of the male. But it is 

 obvious that such characters, from their very lack of conservatism, 

 imply little structural value. 



Now let us examine in these groups of Nematoda, Gordiacea, 

 Crustacea^ Insecta, Arachnida and Myriapoda, to which might be 

 added a number of smaller groups such as the Acanihocephala, the 

 points in which the female is the superior of the male. One has 

 been mentioned, the presence in some Insects of a better developed 

 cerebrum. The other point is the greater complexity of the repro- 

 ductive organs. As homologous in the sexes we consider ovary 

 with testis, oviduct with vas deferens, certain mucous glands, and 

 in some cases vagina with intromittent organ. The male usually 

 possesses as dilations of the vasa efferentia seminal vesicles; except 

 for these and the intromittent organ he has no structures not repre- 

 sented also in the female. The intromittent organ may be very 

 complex as in most Insects and in Spiders (terminal joint of the 

 maxillary palpus), or it may be very rudimentary and simple. 

 Where it is complex the vagina of the female is frequently as cor- 

 respondingly complex {Diptera, Coleopierd). On this account the 

 intromittent organ cannot be regarded in all cases as evidencing 

 greater complexity in the male ; and probably when systematic 

 entomologists employ characters of the external female apparatus as 

 extensively as they have done the male for purposes of diagnosis, 

 they will find the receptive apparatus of the female to be quite as 



