406 POPULAR SCIENCE REVIEW. 
Hogg, J. — Quarterly Journal of Microscopical Science. 1855. Yol. 3, 
p. 235. 
Wenham. — Ibid. 1856. Yol. 4, p. 158. 
Pritchard. — History of Infusoria. 
Sohultze, Max. — 1 . Muller’s Archiv. 1858. P. 330 ; 2. Archiv fur 
Mikroskopische Anatomie. December, 1865. Pp. 374-400 ; 3. 
Das Protoplasma der Rhizopoden und der Pflanzenzellen. Leipzig, 
1863. 
EXPLANATION OF THE PLATE. 
Fig. 1. Pleurosigma angulatum (natural size, -,4^ in.) — a, bands of endo- 
chrome ; 6, fat globules ; c, granular protoplasm ; d, foreign par- 
ticles adhering to the raphe. — After Schultze. 
„ 2. Side view, in which the endochrome is not represented — letters as 
before. — After Schultze. 
„ 3. A specimen treated with Hyperosmic Acid — letters as before. — 
After Schultze. 
„ 4. Nitzschia Sigmoides (natural size, -g-V in.) with adhering Amphora 
minutissima and hair-like processes. Observed at Cambridge. 
„ 5 and 6. Mr. Jabez Hogg’s figures of ciliated Diatoms. 
„ 7. Bacillaria paradoxa. — After Smith. 
„ 8. A single frustule. 
