Mark. — Lepidosteus. 



ABBREVIATIONS. 



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



c.-tcp. 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. 



mpy.cl. Micropylar cell. vit. Vitellus. 



nl. Nucleus. ?>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. 



