XIV LIST OF ILLUSTRATIONS. 



FIGURE PAGE 



tile hairs ; H, hypodermic cells ; if, the membrane surrounding 

 them ; K, nuclei of the olfactory cell ; K^, remains of the 

 earlier upper nucleus ; SK, lower circle of rods ; R8, olfactory 

 rod ; GZ, Geisselzelle ; MZ, membrane forming cell ; if, mem- 

 brane closing the pit . . . . . . . . . . . . 55 



43. Diagram showing structures on the terminal segment of the 



antennae of insects, a, Chitinous cuticle ; 6, hypodermic layer ; 



c, ordinary hair; d, tactile hair; e, cone; /, depressed hair, 

 lying over g, cup, with rudimentary hair at the base ; A, simple 

 cup ; », champagne-cork-like organ of Forel ; h, flask-like 

 organ ; I, papilla, with a rudimentary hair at the apex . . 56 



44. Leg of Stenobothrus pratorum . . . . . . . . . . 62 



45. Sound-bow of Stenobothrus . . . . . . . . . . 63 



46. Diagram of human ear. D, Auditory canal ; E, mouth of Eusta- 



chian tube ; cc, tympanic membrane ; B, tympanic cavity ; o, 

 fenestra ovalis ; r, fenestra rotunda ; s, semicircular canals ; 

 A, cochlea . . . . . . . . . . . . . . 78 



47. Ossicles of the ear. H, Hammer ; Am, anvil ; Am. k, shorter 



process of the anvil ; Am. I, longer process of the anvil ; S, 

 stirrup ; S^, long process of the hammer . . . . . . 78 



48. Section through the ampulla. iV, nerve ; z, terminal cells ; h, 



auditory hairs 79 



49. Tympanal wall of the ductus cochlearis, from the dog. Surface 



view from the side of the scala vestibuli, after the removal of 

 Reissner's membrane, 3oo. I. Zona denticulata Corti. II. Zona 

 pectinata Todd-Bowman : 1, Habeuula sulcata Corti ; 2, Ha- 

 benula denticulata Corti ; 3, Habenula perforata Kolliker. 

 III. Organ of Corti : a, portion of the lamina spiralis ossea 

 (the epithelium is wanting) ; b and c, periosteal blood-vessels ; 



d, line of attachment of Reissner's membrane ; e and e^, epi- 

 thelium of the crista spiralis ; /, auditory teeth, with the 

 interdental furrows ; g, g^, large-celled (swollen) epithelium 

 of the sulcus spiralis internus, over a certain extent shining 

 through the auditory teeth ; from the left side of the pre- 

 paration they have been removed ; h, smaller epithelial cells 

 near the inner slope of the organ of Corti ; k, openings through 

 which the nerves pass ; i, inner hair cells ; /, inner pillai's ; 

 m, their heads ; o, outer pillars ; n, their heads ; p, lamina 

 recticularis ; q, a few mutilated outer hair cells ; r, outer 

 epithelium of the ductus cochlearis (Claudius's cells of the 

 author's) ; removed at s in order to show the points of attach- 

 ment of the outer hair cells . . . . . . . . . . 80 



