LIST OF ENGRAVINGS. XXXIU 



Fig. Page 



406 Diagram illustrating one mode of obtaining images of ob- 



jects, (original) 403 



407 Simple Camera Obscura 404 



408 Law of the refraction of a ray of light 406 



409 Convergence of rays to a focus 407 



410 Convergence by a double convex lens 409 



4 1 1 Spherical aberration 410 



412, 413, and 414 Variations of focal distance, consequent 



upon variations of divergence of the incident rays .... 410 



415 Horizontal section of right human eye magnified, (Home) 412 



416 Straight and oblique muscles of the eye-ball 415 



417 Lacrymal apparatus 417 



418 Eye of Helix pomatia, (Muller) 430 



419 Stemmata of Caterpillar, (Marcel de Serres) 433 



420 Eye of the Scorpio tunensis, (Muller) 433 



421 Conglomerate eyes of Julus terrestris, (Kirby and 



Spence) 433 



422 External magnified view of the compound eye of the 



Melolontha vulgaris, (Straus Durckheim) 435 



423 Ditto of that of a Phalena 435 



424 Section of the compound eye of the Libellula vuUjata, 



magnified, (Duges) 435 



425 Highly magnified view of the outer margin of the pre- 



ceding section, (id.) 437 



426 Portion of the section of the eye of the Melolontha vul- 



garis, (Muller) 437 



427 Portion of the section of the eye of the Libellula, 



(Duges) 437 



428 Portion of the section of the eye of the Melolontha 

 vulgaris, (Straus Durckheim) 437 



430 Interior of the eye of the Perca fiuviatilis, (Cuvier) .... 442 



431 Fibres of the crystalline lens of the Cod, (Brewster) .... 444 



432 Denticulated structure of these fibres, (id.) 444 



433 Section of the eye of the Goose, (Home) 448 



434 Nictitating membrane of a Bird, (Petit) 448 



435 Muscles of the nictitating membrane, (id.) 448 



438 Talitrus, (Latreille) 488 



439 Nervous system of the Talitrus, (Audouin) 488 



440 Nervous system of Cymothoa, Fab. (id.) 488 



441 Nervous system of Maiu squinado, (id.) 490 



VOL. I. C 



