Mare. — Lepidosteua. 



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 folliculi. 



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



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



nl. Nucleus. i's. g. Germinative vesicle. 



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



PLATE VII. 



Fig. 1. Radial section through the granulosa plug which fills the micropylar fun- 

 nel. From an ovarian egg preserved in 0.25 per cent chromic acid, 

 and stained in picrocarminate of ammonia. X 515. 



" 2. Micropylar cell and outlines of the egg membranes in the region of the 

 micropylar funnel, from an ovarian egg preserved in alcohol. Radial 

 section. X 515. 



" 3. Four spermatozoa, dried on the slide. X 472. 



" 4. Micropylar funnel ; optical cross-section as seen from the yolk side of the 

 egg membranes ; showing the oval form of the funnel which is 

 sometimes met with. X 515. 



" 5. Section of an ovarian egg through the germinative vesicle. Only one 

 membrane besides the granulosa present ; it is the villous layer. 

 Preserved in 0.25 per cent chromic acid (48 hours). Stained in 

 alcoholic borax-carmine. X 158. 



