LIST OP ENGRAVINGS. 



XXIX 



^'^- Page 



386 Turbinated bones of the T?<rA:fy, (id.) - . . 287 



387 Nerves distributed to the bill of the Duck, (id.) - - 288 



388 Nasal cavities of the Pero«/2<i;m/27i5, (Cuvier) - . 291 



389 Nasal cavity of the Raia balls or Skate, (Harwood) - 291 



390 Human ear, (Cloquet) - - _ _ _ 299 



391 Posterior surface of the cavity of tlie tympanum, (id.) - 301 



392 Ossicula auditus, or small bones of the tympanum, - - 301 



393 The position of the latter in the tympanum, - - 301 



394 Magnified view oT the labyrinth detached from the surround- 



ing parts, (Breschet^ - - - . . 303 



395 Interior structure of the labyrinth, (id.) - - - 304 



396 Membranous labyrinth, witli its nerves, (id.) - . 304 



397 Cretaceous bodies in the labyrinth of the Dog, (id.) - 304 



398 Ditto in that of the //are, (id.) - - - - 304 



399 Organ of hearing in the Lobster, (Cams) - - 308 



400 Groove in the sac of the former, (id.) . _ . 308 



401 Organ of hearing in the Astacusfliiviatilis, (id.) - 308 



402 Interior view of the same, (id.) - - . . 308 



403 Membranous labyrinth of the i«oyiiM5;)«scG?orms, (id.) - 310 



404 Organ of hearing in the Frog, (Bell) - - - 311 



405 Ear of the Turkey, (Carus) - - - . 31X 



406 Diagram illustrating one mode of obtaining images of objects, 



(original) - - - - _ - 319 



407 Simple Camera Obscura - - - - - 320 



408 Law of the refraction of a ray of light, ... 321 



409 Convergence of rays to a fijcus, - - - _ 322 



410 Convergence by a double conve.x lens, - - _ 324 



411 Spherical Aberration, - - - . _ 324 



412 Variations of focal distance consequent upon variations of di- 



vergence of the incident rays, - - - _ 325 



415 Horizontal section of right human eye, magnified, (Home) 326 



416 Straight and oblique muscles of the eye-ball, - - 328 



417 Lacrymal apparatus, ----.. 330 



418 Eye of //eZix;jowaa'«, (Muller) - - - . 339 



419 Stemmata of Caterpillar, (Marcel de Serres) - - 342 



420 Eye of the -Scorpio fw^icnm, (Muller) - - . 340 



421 Conglomerate eyes of Julus terrestris, (Kirby and Spencc) 342 



422 External magnified view of the compound eye of the Melolon- 



tha vulgaris, (Straus Durckhcim) - - - 344 



423 Ditto of that of a P/ia?cn«, - - - - ;M4 



424 Section of the compound eye of the Libellula vulgata, magni- 



fied, (Duges) --.... 344 



