45 8 Beard. — Reproduction in Animals and Plants. 
conjugation (/ g h) we find that these are all simple fissions, 
and they are bound up, as E. Maupas has demonstrated, with 
differentiations of nuclei into nutritive and reproductive, and 
the formation of new individuals by fission. 
There are no abortive products, and there is no evidence of 
spore-formation subsequent to the conjugation. 
Developmental processes which appear to be nonsensical 
have usually a deep significance. The morphologist who 
encounters such ought always 
to suspect that there is some- 
thing in them requiring close 
attention. 
Apparently meaningless pro- 
cesses having, as O. Hertwig 
observes, a striking similarity 
to the formation of the polar 
bodies during oogenesis, are 
seen in the changes (b c) which 
take place in the micronucleus 
prior to the actual act of con- 
jugation. 
Now, the only reproductive 
products with which we are 
acquainted are gametes, in- 
cluding eggs and sperms, and 
spores. At the stage c there 
are a number of nuclei formed, resulting from the two mitotic 
divisions B and C. In this particular species, Colpidium 
colpoda , three of the four ( c ) in each of the conjugating 
individuals are abortive. Do these cell-nuclei represent 
gametes ? The answer to this appears to be in the negative ; 
they do not conjugate. Before an actual conjugation happens, 
each of the functional ones again divides, and the products 
are those which furnish the actual materials for the conjuga- 
tion, i.e. the gametes. (In this latter division, D, we have 
really a virtual fission of sporozooids to form like conjugating 
gametes.) 
1st. fission 
