Onar. XVII. DEVELOPMENT OF THE BLADDERS. 427 
margins of the rest of the leaf. But strong objections 
may be urged against this view, for we must in this 
case suppose that the valve and collar are developed 
asymmetrically from the sides of the apex and pro- 
minence. Moreover, the bundles of vascular tissue 
have to be formed in lines quite irrespective of the 
original form of the leaf. Until gradations can be 
shown to exist between this the earliest state and a 
young yet perfect bladder, the case must be left 
doubtful. 
As the quadrifid and bifid processes offer one of the 
greatest peculiarities in the genus, I carefully observed 
their development in Utricularia neglecta. In bladders 
about =, of an inch in diameter, the inner surface 
is studded with papille, rising from small cells at the 
junctions of the larger ones. These papille consist of 
a delicate conical protuberance, which narrows into 
a very short footstalk, surmounted by two minute 
cells. They thus occupy the same relative position, 
and closely resemble, except in being smaller and 
rather more prominent, the papille on the outside of 
the bladders, and on the surfaces of the leaves. The 
two terminal cells of the papille first become much 
elongated in a line parallel to the inner surface of the 
bladder. Next, each is divided by a longitudinal 
partition. Soon the two half-cells thus formed sepa- 
rate from one another; and we now have four cells or 
an incipient quadrifid process. As there is not space 
for the two new cells to increase in breadth in their 
original plane, the one slides partly under the other. 
Their manner of growth now changes, and their outer 
sides, instead of their apices, continue to grow. The 
two lower cells, which have slid partly beneath the two 
upper ones, form the longer and more upright pair of 
processes ; whilst the two upper cells form the shorter 
