40 
Tr ne. Xotes on the Pbysiology of tlie Sporopbyte etc. 
immediately below tbe calyptra or perbaps partly witbin it. Tliis 
second curvature was, like tlie first, in tbe plane of tlie incident 
rays, bnt in tbe opposite direction, depressing tbe tip of tbe 
sporopbyte. In many cases, tbe capsnlar rudiment was main- 
tained by tliose two exposed curvatnres in an approximately ho¬ 
rizontal position. In tbe more advanced cases, tbe ends of tbe 
sporopbytes were pointed nearly downward. tliat is. away front 
tlie ligbt. 
Twenty-four liours later, tbe long upward curve of tbe se- 
tal portion was semewbat more rnarked, and in tbe older indi- 
viduals in wbicli tbe capsular rudiments were furt-best- advanced. 
and eonstituted a very well developed. narrowly ebiptical body. 
tbe sbarp curve just below tbe calyptra bad so far progressed 
as to bring tbe capsular rudiments into a nearly perpendieular 
position. In tbe younger sporopbytes tbe general upward curve 
brougbt tbe distal *ends of tbe sporopbytes into a nearly per- 
pendicular position. Immediately below tbe calyptra no curve 
was seen. 
On Marcb 29, about 170 bours after tbe beginning of tbe 
experiment, every capsular rudiment, now in most cases about 
one-balf tbe rnature size. billig in a perpendieular position tbrougb 
a sbarp curve immediately at tbe base, near tbe edge of tbe 
calyptra. Tliis nuirvature, in tbe plane of tbe incident rays. di- 
rected tbe apex of tbe rudiment away from tbe ligbt, toward 
tbe center of tbe eartb. Tbe general upward curve was found 
to bave remained as before. 
On April 1. about 240 bours after tbe beginning of tbe ex- 
periment, tbe capsules, normal and nearly f'tdl sized. were seen 
in every case to bave tbe sperculum directed downward. Tbe 
general setal curve bad been made permanent by tbe internal 
tissue development. 
Turtber observations sbowed tbat normal capsules developed 
witbout any furtber clianges in position. 
IToni tbe data described. it seems justibable to draw tbe 
following conclusions: Tbe young sporopbyte. prior to tbe de¬ 
velopment of a distinct capsular rudiment. is eitlier positively 
beliotropic or negatively geotropic, and tends to assume a per- 
pendicular position wbicli is flxed by tbe furtber development 
of tbe tissues. AVlien in tbe young sporopbyte a capsular ru¬ 
diment bas begun to develop. tbis setal curvature is not mar- 
ked, possibly bec-ause of tbe rigidity of tbe seta tbrougb tbe de¬ 
velopment of meebanical tissue. A sbarp curvature appears just 
below tbe capsule, turning tbe capsular rudiment into tbe per- 
pendicular position as a result of eitlier a positively geotropic 
or of a negatively beliotropic reaction. It appears tbat tliese 
two opposed responses seen in tbe two curvatures can for a time 
take place syncbronously. Tbe question of tbe part played by 
ligbt and by gravity is, bowever. not settled. 
