656 C. H. MARTIN. 
im the animal of masses of chromatin (Tinctin-kérper) de- 
rived from the nuclei of the ingested nematoblasts, but in the 
ciliated embryos and in the young fixed proboscidiform indi- 
viduals there is always to be found a minute sphere of chro- 
matin surrounded by a clear area which, from its position and 
behaviour, must be regarded as a micronucleus. 
It will now be necessary to examine the theories of the 
earlier workers as to the relation between the two individuals 
of Ophryodendron in the light of the observations detailed 
above. 
(1) The conjugation hypothesis of von Koch. 
(2) The parasitic theory of Strethill Wright and Robin. 
(5) The developmental theory of Claparéde and Lachmann, 
Fraipont, and Sand. 
(4) The dimorphic theory of Hincks and Biitschh. 
(1) The Conjugation Theory of von Koch.—Von 
Koch, as has already been shown in the historical introduc- 
tion, put forward the view that the various stages of the 
connection between the vermiform and the proboscidiform 
individual are not to be regarded as stages of budding, but 
rather in the inverse order as stages in a conjugation which 
results in the complete fusion of the copulating individuals. 
This theory is excluded by the observations above made upon 
living forms in which it has been found that the vermiform 
individual is actually budded off from the proboscidiform, the 
whole process from the first appearance of the bud to the 
setting free of the vermiform individual having been ob- 
served to occupy about twenty-four hours. 
(2) The Parasitic Theory of ‘Strethill Wright 
and Robin.—It is interesting to note that both the up- 
holders of this view were working on the species of Ophryo- 
dendron sertularie, in which the vermiform and _pro- 
boscidiform individuals are so different in appearance that it 
is almost impossible to imagine transitional stages between 
them; and the very fact that this theory has been put 
forward must, I think, be regarded as an indication that 
Claparéde and Lachmann’s view of the identity of the two 
individuals is, to say the least of it, strained. 
