370 MONTGOMERY — MORPHOLOGICAL SUPERIORITY. [Oct. 7. 



female — frequently a morphological character, as in the case of all 

 metallic, non-pigmental colors. In these groups then the male may 

 be the morphological superior in the possession of clasping organs 

 or greater development of sensory organs, or of external modifica- 

 tions of form and structural coloration. 



But we must recollect that special clasping organs are not 

 general ; they are found mainly among the Crustacea, by no means 

 in all of them, and usually in correlation with the lack of an 

 intromittent organ. With the development of an intromittent 

 organ, which attains the greatest complexity among all animals in 

 the Insects and Spiders, special clasping organs are rarely found. 

 When they exist they are for the most part comparatively simple 

 modifications of already existing structures, usually limbs. Accord- 

 ingly the possession of clasping organs is a character of little 

 morphological import. 



In regard to the point that the males of these groups are some- 

 times superior in sensory equipment, every comparative anatomist 

 realizes that sense organs are of little morphological value, because 

 they are not conservative and are readily changed or lost. The 

 Medusae have more complex sensory organs than, e.g., the Turbel- 

 laria^ but no one would rank the former higher on this account. 

 Any change of life leading toward loss of locomotion, as in seden- 

 tary and parasitic animals, is followed by degeneration of the sense 

 organs as one of the first modifications ; and in the case of subter- 

 ranean and cavernicolous species, such a comparatively slight change 

 as that from light to darkness, induces the replacement of visual 

 organs by tactile and olfactory. Notice the loss of the lateral line 

 system of sense organs in the case of the emergence of aquatic Ver- 

 tebrates from the water to the land ; or at least, according to a 

 recent theory, their change into non-sensory hairs. That greater 

 size of sense organs by no means induces greater complexity of the 

 nervous system is shown by the comparison made by Forel : ^ in 

 the male ant {Lasius) the compound eyes are largest but the cere- 

 brum (supra- oesophagi al ganglion) most rudimentary, while in the 

 female (particularly the worker) the eyes are smallest but the cere- 

 brum with the greatest number of ganglion cells. In fact we may 

 say, in the light of phylogeny, that greater size and complexity of 

 peripheral sense organs is a more primitive condition than that of 

 small and less complex sense" organs but more concentrated 



^ Ants and Some Other Insects. Translated by Wheeler, Chicago, 1904. 



