Mark. — Lepidosteus. 



ABBREVIATIONS. 



cap. Head of villus. pd. Stalk of villus. 



c.-t. cp. Connective-tissue corpuscle, rx. Root of villus. 



fus. mat. Maturation spindle. st. vil. Villous layer of egg membrane. 



gran. Granulosa. th.fol. Membrana propria of theca f olliculi. 



m py. can. Micropylar canal. vac. Vacuole. 



m py. cl. Micropylar cell. vit. Vitellus. 



nl. Nucleus. vs. y. Germinative vesicle. 



nl. gran. Nucleus of granulosa cell. z. r. Zona radiata. 



PLATE II. 



All the figures of this plate are magnified 515 diameters. 

 Fig 1. Portion of a radial section through the shell of a deposited egg preserved 

 in 5 per cent potassic bichromate. Stained in carminic acid dis- 

 solved in 80 per cent alcohol. Mounted in benzole-damar. 



" 2, 3. Isolation preparations of villi from a mature egg pressed from female. 

 The egg was let fall into 90 per cent alcohol, afterwards soaked in 

 water, and then stained in acetic-acid carmine. Examined in glyce- 

 rine. The heads were of a much brighter rose-color than is shown in 

 the lithographic print. In Fig. 8, c, the villi are seen edgewise; in 

 a, b, and d, flatwise. 



" 4-6. Sections through villi of a mature ovarian egg which was preserved in 

 0.25 per cent chromic acid forty-eight hours, washed in water six 

 hours, and further hardened in grades of alcohol. Stained in alco- 

 holic borax-carmine (Grenacher). In Figs. 4, 5, the ends of the villi 

 are seen ; in Fig. 6, the sides. 



" 4 Sections of stalks from the pole opposite the micropyle. 



" 5, 6. Sections of stalks from near the micropyle. 



" 7. Radial section of an egg preserved in Perenyi's fluid (4£ hours) followed 

 by alcohol and stained in alcoholic borax-carmine, showing an inner 

 portion of the zona radiata partly detached from the outer portion. 

 It is not a separate membrane. 



" 8. Radial section through zona and villous layer of an egg preserved in 5 per 

 cent potassic bichromate, stained in carminic acid in 80 per cent alco- 

 hol, and mounted in benzole-damar. 



