the Genus Urophlyctis . 93 
many cysts are connected with each other by narrow tubes 
originating from the cysts (Fig. 17). Each cyst throws out 
pointed processes which penetrate the parenchyma, and then 
at intervals widen out again into fresh cysts ; each new cyst 
does the same, and so on (Figs. 17-22). It often happens 
that many such tubular processes spring from one cyst ; they 
may be short or long, wide or narrow ; and they may 
frequently be followed a long way through the tissue. The 
tubes are provided with the same kind of thick membrane 
as the cysts. The observation of young processes and small 
cysts shows that the protoplasm affected by the parasite 
enters them, and that this protoplasm leads the way for the 
Urophlyctis that follows at a later period. In any case I have 
not succeeded in tracing the hyphae of the Fungus in the 
protoplasm of the youngest swellings. The parasite, however, 
soon follows, and entering these swellings often forms new 
spores within their wider portions (Fig. 18). 
It is only in the narrowest portions of the channels, as 
shown, for instance, in Figs. 22 and 23, that the formation 
of spores is suppressed. The majority of the cysts of one 
swelling are therefore connected with each other, or rather 
they are excrescences of a single cyst pervading the parenchyma 
of the swelling. 
The only difference between this growth and that of the gall 
of Urophlyctis Kriegeriana is that the development of the 
cell attacked by the latter parasite, and consequently also that 
of the gall, is limited. On the other hand, in the case of U. 
leproides , the cell attacked by the Fungus grows without limit ; 
it pervades the parenchyma, the frequent divisions of which 
are the cause of the cell’s growth into the new tissue, while 
it reacts on the parenchyma as a stimulus for still further 
divisions. Thus the large botryoid swellings on the upper 
part of the root of Beta vulgaris, var. rapacea , make the 
disease very conspicuous. 
The wall of the infected cell is also in this case very thick, 
and it never possesses sieve-like perforations as in U. pulposa 
and U. major. The formation of spores takes place in exactly 
