260 
AV. M. AA^heeler 
The M. hrevicirrum alluded to in this passage is a free-living 
species of which v. Graff says in another place ('84b, pag. 43): 
»Since in individuals of 0.24 mm diameter the vasa deferentia and 
tbe seminal vesieles are filled with spermatozoa, whereas the eggs 
are but little developed, it may be concluded that the male apparatus 
is earlier developed than the female.« 
These two passages taken together with v. Graff’s earlier ob- 
servations on the young of M. glahrum show how closely he came 
to the true interpretation of the hermaphroditism of the Myzostomidae. 
It is indeed stränge that he failed to detect the red thread of pro- 
tandry which might have been conceived to explain the apparently 
very heterogeneous sexual condition s of the group. 
In the same year as v. Graff s final observations on the Cysticola, 
appeared Beard’s dissertation on the life-history and development ot 
Myzostoma ('84). So far as the sexual phases are concerned, Beard’s 
observations are confined to a single species, M, glahrum, The small 
individuals on the larger ones were observed, but Beard says of 
them (pag. 569): »they are not young ones but fully developed 
males, usually with numerous fully developed and functional 
spermatozoa. In fact M. glahrum is not as all previous ob- 
servers, including the latest Prof. Graff, have considered, 
a simple hermaphr odite, but is hermaphrodite with fully 
developed and highly organized males.« In these small in- 
dividuals, which he calls »complemental males«, Beard foimd a »total 
absence of all trace of female organs«. It is in vain that we 
search this paper for the feeblest fact to prove that these males are 
»fully developed«, that they do not grow beyond the stage 
in which Beard found them. A deceptive argument from analogy 
with the Cirripedia takes the place of fact, and we are brought at 
the end of the paper by a kind of hocus pocus, not uncommon in 
morphological writings, to the far-reaching conclusion that herma- 
phroditism in general is derived from gonochorism and not vice 
versa as most authors maintain. In Beard’s paper the cysticolous 
Myzostoma inßator and M. murrayi are confidently put down as »per- 
fectly unisexual)«, an expression which should be compared with 
to this view all the cysticolous Myzostomes of a given species would not 
be cyst-pr oducing but only those which, instead of entering the orifice of 
a preformed gall in their juvenile stage, happen to settle between the arm-joints 
or contrive to work their way into the calcareous skeleton of the Crinoid. 
