xiv ILLUSTRATIONS 



FIG. PACE 



24 to 27. Developing ova from ovary 120-121 



28. Ovary at birth, showing primordial follicles . . . .123 



29. Young oocyte 126 



30. Young human Graafian follicle . . . . . .127 



31. Human ovum at termination of growth period . . .128 



32. Human ovum examined fresh in the liquor folliculi . . .129 



33. Recently ruptured follicle of mouse 144 



34. Early stage in formation of corpus luteum of mouse . . 145 



35. Late stage in formation of corpus luteum of mouse . . .146 



36. Corpus luteum of mouse fully formed . . . . 147 



37. Section through old corpus luteum ...... 153 



38. Section through follicle in early stage of degeneration . .155 



39. Section through follicle in late stage ..... 157 



40. Section through human testis and epididymis . . . .166 



41. Section through testis of monkey . . . . . .167 



42. Section through portion of two seminiferous tubules in testis 



of rat 169 



43. A cell of Sertoli with which the spermatids are beginning to be 



connected (human) ........ 170 



44. Diagram illustrating the cycle of phases in spermatogenesis . ib. 



45. Scheme of spermatogenesis and oogenesis . . . . .171 



46. Human spermatozoa on the flat and in profile . . . .173 



47. Human Spermatozoa . . . . . . . .174 



48. Different forms of spermatozoa from different species of 



animals .......... 175 



49. Diagram illustrating wave-like movement of swimming sperma- 



tozoon . . . . . . . . . .177 



50. Successive stages in the fertilisation of an ovum of Echinus 



esculentus, showing the entrance of the spermatozoon . 188 



51. Three stages in the conjugation of male and female nucleus 



(Echinus) 189 



52. Fertilisation process in bat's ovum . . . . . .190 



53. Passage of convoluted seminiferous tubules into straight 



tubules, &c 228 



54. Transverse section through the tube of the epididymis . . 229 



55. Transverse section through commencement of vas deferens . 230 



56. Section through part of human prostate ..... 235 



57. Section through prostate gland of monkey . . . .237 



58. Transverse section through adult human penis . . . 243 



59. Section through erectile tissue ....... 244 



60. Part of transverse section through penis of monkey . . . 245 



61. Distal end of ram's penis, showing glans and filiform appendage 247 



62. Transverse section through filiform appendage of ram . . 248 



