Untitled

Fig.		Page
226 .	Part of the skeleton of Cannorhaphis ( do. )	472
227 .	A Nassellarian skeleton, Callimitra carolotae ( do. )	472
228 ,ã9.	Portions of Dictyocha stapedia ( do. )	474
230 .	Diagram to illustrate the conformation of Callimitra	476
231 .	Skeletons of various radiolarians (Haeckel)	479
232 .	Diagrammatic structure of the skeleton of Dorataspis ( do. )	481
233 ,ã4.	Phatnaspis cristata (Haeckel), and a diagram of the same	483
235 .	Phractaspis prototypus (Haeckel)	484
236 .	Annular and spiral thickenings in the walls of plant-cells	488
237 .	A radiograph of the shell of Nautilus (Green and Gardiner)	494
238 .	A spiral foraminifer, Globigerina (Brady)	495
239 ã42.	Diagrams to illustrate the development or growth of a logarithmic spiral	407ã501
243 .	A helicoid and a scorpioid cyme	502
244 .	An Archimedean spiral	503
245 ã7.	More diagrams of the development of a logarithmic spiral	505, 6
248 ã57.	Various diagrams illustrating the mathôÙeôÙmatôÙiôÙcal theory of gnomons	508ã13
258 .	A shell of Haliotis , to shew how each increment of the shell constitutes a gnomon to the preexisting structure	514
259 ,ã60.	Spiral foraminifera, Pulvinulina and Cristellaria , to illustrate the same principle	514, 5
261 .	Another diagram of a logarithmic spiral	517
262 .	A diagram of the logarithmic spiral of Nautilus (Moseley)	519
263 ,ã4.	Opercula of Turbo and of Nerita (Moseley)	521, 2
265 .	A section of the shell of Melo ethiopicus	525
266 .	Shells of Harpa and Dolium , to illustrate generating curves and gene	526
267 .	DãOrbignyãs Helicometer	529
268 .	Section of a nautiloid shell, to shew the ãprotoconchã	531
269 ã73.	Diagrams of logarithmic spirals, of various angles	532ã5
274 ,ã6,ã7.	Constructions for determining the angle of a logarithmic spiral	537, 8
275 .	An ammonite, to shew its corrugated surface pattern	537
278 ã80.	Illustrations of the ãangle of retardationã	542ã4
281 .	A shell of Macroscaphites , to shew change of curvature	550