1904.] MONTGOMERY — MORPHOLOGICAL SUPERIORITY. 369 



organs — glandular organs not present in the male, ovaries with 

 lateral diverticula, while the testes are simple tubes. Among the 

 dicecious Ne7?iatoda the male is always the smaller, with copulatory 

 spicules and a bursa not reprcbented in the female ; also the testes 

 are usually impaired, a higher condition, i.e., one involving more 

 modification, than the condition in the female where there are 

 paired ovaries. On the other hand the female is larger, with 

 the genital ducts more complicated and with a receptaculum 

 seminis ; and unlike the simpler male condition where the genital 

 ducts open into a cloaca, the female shows the higher morphologi- 

 cal state of a separate aperture for the reproductive ducts (with the 

 single exception of Cloacind). In both these groups, then, the 

 female appears structurally more advanced. In the group of 

 Insecta, Arachnida, Crustacea, Opisihogoneata and Progoneata we 

 find forms that in many respects appear the most specialized of all 

 the Invertebrates (not excluding the Tunicata). They are all 

 essentially terrestrial forms, for there is good reason to conclude 

 withSimroth^ that even the Crustacea arose from ancestors that 

 lived upon the land, or at least in very shallow water, though most 

 of the modern representatives are aquatic. In these annulate 

 groups, contrary to the groups considered in the preceding para- 

 graph, we find the association of terrestrial life necessitated thereby 

 an intimate copulation process and notable differences in the repro- 

 ductive organs, also secondary sexual differences. In these forms 

 the male is almost always smaller than the female, notably so in 

 many Aranece (particularly of the family Argiopidce). The only 

 exceptions to this rule that occur to me are a itw beetles and 

 certain Hymenoptera. The male may be more complex than the 

 female in the possession of clasping organs, and sometimes in the 

 more complete development of sensory organs. So in the ants and 

 flies particularly the compound eyes are frequently larger in the 

 males, and sometimes differ from those of the female in being con- 

 fluent (a secondary condition). The most important olfactory and 

 tactile organs of Insects, the antennae, are frequently larger and 

 more complex in the males, as shown especially in the case of the 

 Moths; and in the Spiders the special tactile organs, long hairs, are 

 in some cases relatively and even absolutely larger in the males. 

 Then it is v/ell known that in these forms the male differs frequently 

 in external form, and often is more brightly colored than the 

 1 Die Eutstehuiig der Landtiere. Leipzig, 1889. 



