250 —— Prof. G. Gulliver on Raphides and other Crystals. 
XXIX.— Observations on Raphides and other Crystals. 
By Grorce GuLuiiver, F.R.S. 
[Continued from p. 56. ] 
Quillajee.—The crystals in the wood or bark of Quallaja sapo- 
naria, which were long ago well described by Edwin Quekett, 
are very characteristic of the genuine article. In a sample from 
Messrs. Butler and M‘Culloch, I find these crystals lymg in 
great numbers along the liber and mesophleeum. They are 
commonly about ;4,th of an inch long and 5;);sth thick, four- 
sided rectangular prisms, each of the faces equal, and the ends 
tipped with short pyramids. But they vary in form. Their 
ends may be like the edge of a chisel or wedge, and occasionally 
as if the shaft of the crystal had been cut through obliquely 
from one angle or face to the opposite one; besides, the prisms 
may be triangular. Though they are so very plentiful, they 
occur for the most part singly, sometimes two or three partially 
fused together, and never in bundles, in which characters they 
further differ from true raphides, and closely resemble many of 
the crystal prisms of Inidaceze and some other Monocotyledones 
(‘ Annals,’ Sept. 1863 and April and May 1864). Quekett de- 
scribes each separate prism of Qui/laja as having a close -invest- 
ment or cell, but no loose one, of cellulose. 
Melastomacee.—A species of Melastoma, at Redleaf, affords 
an abundance of spheraphides in the endophloeum and meso- 
phlceum, but no raphides either in the bark or leaves. 
Crassulacee, Ficoidee, and Cactacee.—A complete examination 
of these orders would be interesting and useful. Among the 
few species formerly examined (‘ Annals,’ May 1864) raphides 
were always found abundantly in Mesembryanthemum, and never 
at all in Crassulaceze and Cactacex, although spheraphides and 
short four-sided prisms were seen to abound in the last-named 
order. These prisms sometimes appeared either abruptly trun- 
cated, tipped with low pyramids, or with the ends as described 
in Quillajeze, &c., the tips commonly forming a part and pro- 
jecting on the surface of the spheraphides. Lately I have 
again examined the plants already specified, and a few others, to 
wit, Sedum speciosum, S. Fabaria, Epiphyllum Russellianum, Ce- 
reus crenatus, and two species of Mesembryanthemum. The result 
was still the same—a profusion of raphides in Mesembryez, and 
none in Crassulaceze and Cactacee. Raphides were seen abun- 
dantly in the corolla, style, and ovary, but not in the stamens 
and ovules, of Mesembryanthemum tricolor, and in the petals and 
filaments of M. tortwosum. In these last two parts, and in the 
ovary and pistil, the raphides were smaller and more fragile than 
in the leaves and stem; and, as I have described in other spe- 
