( xiii ) 
LIST OF PLATES. 
PLATE PAGE 
I. — Some Optical Characters of Crystals To face 1 
II. — Abbe’s Apertometer „ 19 
III. — Stylaster stellulatus and Tabipora musica „ 41 
IV. — Blood-corpuscles of Amphiuma tridactylum „ 57 
V. — Blood-corpuscles of Amphiuma, Frog, and Man „ 97 
VI. — Cheyletus flahelUfer 133 
VII. — Elements and Computation of the a Immersion Objective made 
by Mr. R. B. Tolies and owned by Mr. Crisp „ 142 
VIII. — Bacterium termo. Spirillum volutans, Vibrio rugula, Spirillum untlula, 
and Bacillus ulna „ 170 
IX. — Bacterium lineola, Bacillus subtilis, Bacterium termo „ 170 
X. — Framework of Mastax of Melicerta ringens „ 176 
XI. — Mastax of Gonochilus volvox „ 176 
XII. — Dermal Tubercles (“ granicones”) and Teeth {Nuthetes destructor) „ 233 
XIII. — Dermal Scutes ( Theriosuchus pusillus) „ 233 
XIV. — New Genera and Species of Diatomacese „ 237 
XV.— Ditto 237 
XVI. — Cheyletus venustissimus ,, 313 
XVII. — Improvements in the Micro-spectroscope „ 326 
LIST OP WOODCUTS. 
PAGE 
Cothurnia furcifer 49 
Diffraction Images of Bleurosigma angulatum with the Now Oil-immersion 
Objective 54 
Diagram illustrating Professor G. G. Stokes’ paper on the Apertures of 
Microscopic Objectives 141 
Ditto ditto 142 
Diagram of Tolies’ ^ Objective 143 
Appearance of P. angulatum when the Central Dioptric Beam of Light is 
excluded 186 
An Improved Form of Hot Stage 191 
Colonel Woodward’s Right-angled Prism for the Illumination of Balsam- 
mounted Objects 246 
Mr. Gundlach’s New Cover Adjustment for Object-glasses 252 
Lantern for the “ Projection of Microscope Photographs” 295 
Miniature Microscope 296 
Diagram illustrating Mr. Wenham’s paper on the Angle of Aperture of 
Objectives 324 
Outlines of Zooids of Millepora alcicornis 341-2 
A New Device for Dark- Field Illumination 347 
Mr. Bevan Lewis’s Freezing Microtome 359 
VOL. I. G 
