86 
Oliver . — On Pkysostoma elegans , Williamson , 
It is at this region, were the section cut in the true horizontal plane, 
that the relations might be regarded as perfectly comparable to the ‘ canopy 5 
of a Lagenostoma . Though practically insignificant here, attention is drawn 
to the fact, as it serves to show how very slight is the readjustment 
necessary in the mutual relations of the parts to pass from the Physo- 
stoma- to the Lagenostoma - condition so far as this particular feature is 
concerned. 
At the level where they are still joined tangentially (PI. VI, Fig. 13), 
the tentacles have a radial diameter of 
•36 millim., and a tangential diameter 
of -4 millim. The radial dimension, how- 
ever, falls almost at once in correspon- 
dence with the expansion of the nucellus 
to form the pollen-chamber, whilst the 
tangential dimension more nearly holds 
its own for some little distance, as the 
bulging wall of the pollen-chamber pre- 
vents the whorl of tentacles in this region 
from contracting its perimeter. Above 
the pollen-chamber the arms gradually 
taper, the smallest transverse section of 
the distal part of an arm that has come 
under observation having a diameter (in- 
clusive of the epidermis) of 77 g. 
The study of numerous longitudinal 
and oblique sections of the seed shows 
that the arms may attain a length of 
2 millims. from the zone of their inser- 
tion — that is to say, their extension 
beyond the summit of the pollen-chamber 
is about 1 millim. 
As regards their position, the ma- 
jority of preparations show the proximal 
parts of the arms to have formed an 
enclosure to the pollen-chamber, one deep. Occasional specimens, how- 
ever, show that one or another of the arms have slipped out of rank as 
in Prof. Bertrand’s section (M.H. 371, PI. V, Fig. 3, t 1 ). 
With the distal portions of the arms, more irregularity of arrangement 
obtains. Sometimes they are found in an untidy bunch — as is well illus- 
trated by an oblique section cut well above the pollen-chamber (Text- fig. 5)3 
the highest that has come under observation. In this figure the interior 
tissue of the arms is blackened, whilst the epidermis and its appendages 
are drawn in outline. Four of the nine tentacles— distinguished by their 
Text-fig. 5. Oblique section across the 
tip of a seed, above the pollen-chamber. 
Nine tentacles are shown. Four of the 
lower ones, cut somewhat tangentially, are 
subtended by numerous cross-sections of 
epidermal hairs which were inserted at 
a lower level. The body of each tentacle 
is drawn black, x 34. U. C. L., K. 36, a. 
