264 
W. M. Wheeler 
examine different stages of the more typical and commoner M. cirri- 
ferum^ and although I showed in my preliminary note that this 
species is protandric and furnishes the eine to the sexual conditions 
in the other free-living forms, he does not once allude to these 
ohservations. Why should this species, which is undoubtedly pro- 
tandric, be quietly ignored in a discussion which has for its first 
object to determine whether the hermaphroditism of Myzostomes is 
or is not protandric? 
2) I should like to know where Beakd has ever shown that 
his so-called complemental males do not grow beyond the stage in 
which he found them. Certainly a few months’ sojourn at Naples 
is quite inadequate to show any such thing for a slowly growiug 
form like M. glahrum^ and since »complemental males« are of such 
very rare occurrence in the animal kiugdom, the bürden of proof 
must lie with bim who denies that the small individuals ultimately 
develop into the large hermaphrodite and female specimens. This 
demonstration might be dispensed with only if it could be shown 
that the Organization of the complemental male differed to such an 
extent from that of the larger hermaphrodite that the latter could 
not be supposed to pass through a stage like the former. And even 
in this case, those who are acquainted with the possibilities of growth 
and metamorphosis w^ould hardly rest satisfied with mere assertion. 
3) As a matter of fact, there is absolutely uothing in the Organi- 
zation of the so-called complemental male which prevents it from 
being a stage through which the large hermaphrodite might pass. 
Indeed, we must assume that it is very similar, if not identical, 
with a stage . through which the hermaphrodite must pass. It is a 
fact, easy of Observation, that in the embryos and young of the 
Metazoa in general the nervous System is relatively more volumiiious 
than in the adult. This we find to be the case with the nervous 
System in the so-called complemental males of M. glahrum when 
compared with the nervous System of the large hermaphroditesh 
It is also easy to observe that within this series of different-sized 
individuals which would be regarded by Beard as complemental 
males, the body-cavity (»uterus«) and intestine pass from simple 
median tubes to ramified structures, thus leading by gradual steps 
to the earliest conditions of these Organs in the hermaphrodites. 
1 Beard appears to have observed this, although the truth of his remark 
{'85, pag. 570) that »in the males the nervous System seems to be richer in ganglion 
cells than in the hermaphrodite« may well be doubted. 
