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 rare in the root. 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 A'erides odorata : several bundles of raphides, but not abounding. Bit of leaf of Trichotosia (a section oiEria) : 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 Mossice (leaf and swollen part of stem) : raphides abun-dant. Phaius grandifolius : bundles of raphides swarming in the leaves, bulb, and root-fibres ; in the bulb, raphis-cells veiy large and hyaline, also a profusion of beautiful, conical, large starch-granules, average length -^rhi^^) and breadth — i— 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 sphseraphid tissue (Annals, Sept. 1863, PI. IV. fig. 13) ; the diameter of each of the sphseraphides regularly about -g-oVotb of an inch. Ansellia: raphides rather numerous. Bolbophyllum : raphides pretty numerous. Aracea. — 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 CBthiopica, 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 Sti^uctural Variation among the Dijfflugian Rhizopods. By G. C. Wallich, M.D., F.L.S., &c. [Plates XV. & XVI.] The wide range of variation manifest in the external characters of the non-testaceous Amoeban and Actinophryan Rhizopods has been already discussed by me in several papers which have
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