1875.] Difficulties of Darwinisin. 329 
former—must be horned likewise. The analogy, however, 
is somewhat strained. The horns in one case differ signally 
from the horns in the other. The Dynastide—the most 
decidedly cornuted of all the Lamellicornes—do not remove 
or burrow in dung, and their metropolis is a region remark- 
ably poor in ruminants. Still the idea of certain structural 
types reappearing, in a more or less modified form, in dif- 
ferent sections of the organic world, may yet prove fruitful, 
and should not be entirely lost out of view. How it may 
best be harmonised with the do¢trine of Descent is not a 
subject for present consideration. 
Another difficulty for ‘‘ Selection ” is the existence of tri- 
morphous species. ‘Thus in Papilio Memnon there are two 
distinct forms of females, the one nearly resembling the 
male, and the other decidedly unlike. A single brood of 
larve, the issue of either kind, comprises at once males and 
specimens of both kinds of females. The males do not 
appear to show any exclusive preference for either form. 
On what principle has this anomaly arisen? Is it the 
initial step to the formation of two distinct species? If 
not, what end does it subserve that would not be equally 
well secured were the females all of one type ? 
Turning to a totally different point, we find it a general 
rule that—in the Vertebrata and Articulata—the sexual 
organs are situate at or near that extremity of the trunk 
which is farthest from the head. In spiders, however, it is 
asserted that these organs in the male are placed in one of 
the legs. Now, that this very peculiar arrangement is an 
advantage to male spiders we do not dispute. It is nothing 
uncommon for the female spider to destroy her mate, and 
hence a conformation which permits of intercourse without 
the close contact required in other forms of animal life may 
be beneficial to the male.* But by what process has such a 
change been brought about? We feel utterly unable to 
conceive even of the first stages of the needful transitions. 
It would seem that any male animal in which the generative 
organs were by some malformation removed from their usual 
site, even to a small extent, would be placed at a disadvan- 
tage, and be less likely to leave posterity than one of the 
normal structure. If we consider the intermediate positions 
through which the male organs of the spider must have 
gradually travelled in the course of myriads of generations, 
we shall be convinced that whatever advantages their present 
* A somewhat similar arrangement prevails in the Octopus, which might 
almost be characterised as a sea-spider, though not ranking among the Arti- 
culata. 
