6 14 Trow . — The Karyology of Saprolegnia. 
vacuole-like fusion-nuclei and the true vacuoles. He comes 
to the conclusion that the male gametangia are functionally 
impotent, and has developed a theory to explain his observa- 
tions which would be all the more interesting and valuable 
if these were entirely beyond question. 4 We have,’ he says, 
‘ a case of multiple endogamous union of potential gametes.’ 
Hartog further points out that the young oospore is uni- 
nucleate in Saprolegnia , but frequently binucleate in Achlya. 
He has apparently made no observations on the germinating 
oospores, and, so far, has unfortunately given no figures. 
Dangeard’s (’90 a) results are in accordance with those of 
Hartog up to a certain stage. The differences on the really 
critical points, however, are very great. This author, putting 
aside the question of vacuoles, finds no evidence of fusion- 
nuclei. He says, that from the vacuolated stage onwards to 
the formation of the young oospore, one sees only fine 
granules of chromatin dispersed in the protoplasm, — 4 la 
substance des noyaux s’etre eparpillee ’ ; and also asserts that 
the ripe oospore is multinucleate, but as to the origin of these 
nuclei he can only offer conjectures. 
Dangeard suggests, in addition, that the c Kern-fleck 5 of 
De Bary seen in the young oospore is the commencement of 
the fatty mass and not a nucleus at all, and that certain small 
deeply staining bodies which make their appearance in the 
young oospore are globules of glycogen. It is well to pay 
some attention to these curious and bewildering observations, 
— on which I hope to be able to throw some light — as they 
so plainly indicate the special difficulties of the investigation. 
Dangeard leaves the question of fertilization undecided. 
Humphrey’s (^92) conclusions do not differ to any great 
extent from those of Hartog. In particular, both of these 
botanists are agreed as to the reduction of the nuclei in the 
oogonium by a process of fusion, the uninucleate character 
of the ripe oospores, and the impotency of the antheridia. 
Humphrey, however, finds no evidence of division of the 
nucleus taking place in the antheridia. His figures, of which 
comparatively few deal with the histology, are of very con- 
