Dr. G. C. Wallich on Structural Variation in Rhizopods. 215 
other parts of fructification (no leaf examined) ; hairs of scape 
jointless, and not glandular. Dendrobium nobile: raphides 
abundant in very young leaves, less so in old leaves and stem, 
and very rarein theroot. D. pulchellum: bundles of raphides in 
the stem and fleshy leaves, and very rare in the root. Leaf 
of another Dendrobium: raphides rather scanty, but large. 
Leaf of Aérides odorata: several bundles of raphides, but not 
abounding. Bit of leaf of Trichotosia (a section of Eria): bundles 
of large raphides abundant in cells, and numberless smaller 
raphides in the field of vision ; hairs of leaf red, smooth, jointless, 
swollen at base, and not glandular. Schomburgkia crispa: bundles 
of raphides abundant in swollen part of stem, scarcer in its thin 
part and leaf; woody part of stem made up of dotted vessels. 
Cattleya Mossie (leaf and swollen part of stem) : raphides abun- 
dant. Phas grandifolius: bundles of raphides swarming in 
the leaves, bulb, and root-fibres ; in the bulb, raphis-cells very 
large and hyaline, also a profusion of beautiful, conical, large 
starch-granules, average length ~},th, and breadth ~1,th of 
an inch. Brassia (a bit of the leaf, as also in all the follow- 
ing): raphides, but not very plentiful. Oncidium: very few 
bundles of raphides. Megaclinium: raphides abundant, and a 
beautiful subcuticular spheraphid tissue (Annals, Sept. 18638, 
Pl. IV. fig. 13); the diameter of each of the spheraphides 
regularly about =;;th of aninch. Ansellia: raphides rather 
numerous. Bolbophyllum: raphides pretty numerous. 
Aracee.—Among some fragments of plants to aid this inquiry, 
which were obligingly supplied by Mr. Cox, the excellent super- 
intendent of the Redleaf Gardens, is part of the leaf of Richardia 
ethiopica, which I find abounding in biforines, the raphides 
escaping, under gentle pressure, regularly from both ends of the 
oval cells. 
Edenbridge, Feb. 12, 1864. 
Erratum.—In the February Number, page 121, line 34, for “ classifi- 
cation ” read “ discrimination.” 
[To be continued. ] 
XXVI.—On the Extent, and some of the Principal Causes, of 
Structural Variation among the Difflugian Rhizopods. By 
G. C. Wauticu, M.D., F.L.S., &e. 
[Plates XV. & XVI] 
Tue wide range of variation manifest in the external characters 
of the non-testaceous Amceban and Actinophryan Rhizopods 
has been already discussed by me in several papers which have 
