no Oliver. — On Physostoma elegans , Williamson , 
3. The characters of the free portion of the integument or ‘ canopy ’. 
In L. Lomaxii the free portion of the integument forms a chambered shell 
which surrounds the pollen-chamber. The number of the chambers is 
nine, and each is penetrated by a vascular strand. In L. ovoides the 
structure is essentially the same, excepting that the number of chambers 
is usually eight. At the level at which the integument merges with the 
nucellus its chambered character is lost. 
In Physostoma this canopy is represented by the whorl of, usually, 
ten tentacles, which are approximated — but never fused — to form a conical 
investment around the pollen-chamber. Comparison of these seeds points 
to the equivalence of the tentacles of the one with the fused chambers of 
the others. Physostoma might be described as a Lagenostoma with unfused 
chambers (cf. Text-figs. 1, 2, and 10 on pp. 76, 77, and 109). 
4. The mucilage hairs of the integument. The whole series of seeds 
agree in showing the ‘ mucilage-habit ’ which they exhibit in differing degrees. 
In L. L omaxii the palisade layer of the integument bears little pegs, 
the summits of which are sometimes found curiously displaced, as though 
raised up by an emission of mucilage from the prismatic cells below or from 
the wall upon which they are seated. 1 
Though the pegs have not been observed, evidence of a similar 
emission of mucilage has been detected in the case of L. ovoides , 2 whilst in 
Conostoma oblongum the common outside membrane of the very conspicuous 
palisade-cells of the testa is sometimes found ‘ blown off as though a number 
of these cells had emitted a quantity of mucilage. 
In Physostoma a differentiation into separate prismatic cells and pegs 
is not met with, but the superficial cells on the ridges and tentacles are 
expanded into the well-known tubular processes which may well have had 
a mucilaginous secretion as contents. 
The agreement between the several seeds is thus a striking one, and, 
taken in connexion with the other points of resemblance, is consistent with 
a derivation of the group from some common antecedent form. 
5. The epidermal cells (prismatic cells in L. Lomaxii and ovoides , and 
the epidermal cells in Physostoma ) were arranged in longitudinally-running 
linear series. 
6. The vascular system in all these seeds has essentially the same 
distribution. 
7. The many-layered tapetum of the nucellus or ; megaspore-jacket 
so characteristic a feature in Physostoma is also met with in Conostoma ; 
there is also some slight grounds for the suspicion that it may have been 
present at early stages of development in L . Lomaxii . 3 
1 Oliver and Scott, loc. cit., PI. X, Figs. 28, 28 A, 28 B, and PI. V, phot. 12, and p. 206. 
2 In the specimen R. 22 in the University College Collection, the appearance is identical with 
that shown for L. Lomaxii , in Oliver and Scott, loc. cit., PI. V, Fig. 12. 
3 Cf. p. 99. 
