54 Transactions of the 
lived a much longer life than it does now, as well as a very dif- 
ferent one. 
What then can have led to so remarkable a degeneration ? 
What can have reduced the male to the rare, rudimentary, short- 
lived creature that he is at present ? It might be suggested that 
an abnormal development of the special male organs has taken 
place in some specimens at the expense of the other organs of the 
body, and that an unusually numerous and vigorous offspring has 
descended from such specimens ; inheriting the peculiarities of 
their parents, and supplanting the feebler and normal tribes ; such 
a process, if continued, leading in time to the conversion of the 
male into what is now little more than a movable “ hag of sper- 
matozoa.” 
But this guess, if accepted as an explanation, only meets half 
the difficulty. How is it that parthenogenesis among the females 
accompanied degeneration among the males ? For, of course, if 
the males occur only at certain seasons of the year, and live but an 
hour or so, parthenogenesis is a necessity among females whose 
lives are so short that scores of generations succeed each other 
between two appearances of the males. Then too is there any 
connection between the degeneration of the male and its rare 
occurrence ? And how comes it that some female Rotifer, in no 
way distinguishable from hundreds of others, should, unlike them, 
lay male eggs instead of female ones ? And why should the same 
female never lay eggs of different sexes ? 
Questions such as these are much easier asked than answered ; 
and yet it is the hope of finding a satisfactory answer to them that 
constitutes the chief charm of natural science, which without its 
speculations and hypotheses would become a barren record of com- 
paratively uninteresting facts. 
I cannot pretend to offer any solution myself of these difficul- 
ties ; and, indeed, in the case of the Rotifers it seems almost hopeless 
to expect ever to get a solution of them : for the small size of these 
creatures prevents us from studying them except under conditions 
that are very unfavourable both to life and health. 
