Eigenmann. — Egg Membranes. 



PLATE I. 



Figures 1-13 are of F undid us heterocJitus. 



Fig. 1. Surface view of one of the smallest filament-bearing eggs of October 27. 

 Diameter of egg, 0.16 mm. Examined fresh. X 750. 



" 2. Surface view of another egg of the same size and date, with somewhat 

 larger filaments. Examined fresh. X 425. 



" 3. Tangential section of an ovarian egg 0.15 mm. in diameter. The ovary 

 was hardened, December 23, in Flemming's chromic-osmic-acetic mix- 

 ture, and subsequently stained with hematoxylin. X 425. The section 

 is seen from its inner surface. 



" 4. Tangential section of an egg from the same ovary with longer filaments. 

 X 425. This section is also seen from its inner surface. 



" 5. Surface view of an egg of October 27, about 0.23 mm. in diameter. 

 Examined fresh. X 425. 



" 6. Tangential section of an egg 0.25 mm. in diameter, from the same ovary 

 as Fig. 3. X 750. 



" 7. Surface view of a ripe (June) egg from which the granulosa cells had been 

 removed, showing the network of ridges between their bases. Exam- 

 ined fresh. X 750. 



" 8. Radial section of the egg represented in Fig. 3. Transsections of fila- 

 ments are seen at Jd. X 425. 



" 9. Radial section of an egg of May 2, about 0.8 mm. in diameter. Preserved 

 in Perenyi's fluid, and stained with picrocarminate of lithium. X 750. 



" 10. Tangential section of an egg of December 23, about 0.4 mm. in diameter. 

 From the ovary mentioned under Fig. 3. X 425. 



" 11. Radial optical section of a ripe egg shortly after being forced from the 

 ovary (June 1). Examined fresh. X 50. 



" 12. Base of one of the filaments of the ripe egg. Examined fresh under pres- 

 sure. X 750. 



" 13. Radial section of an ovarian egg of November 23. Preserved in Perenyi's 

 fluid, and stained with Grenadier's alcoholic borax-carmine. X 750. 



Figures 14-22 are of Pygosteus pungitius, all except Figure 20 being of eggs 

 from a single ovary, which was cut transversely. 



" 14. Radial section through an ovarian egg 0.15 mm. in diameter. The ovary 

 was preserved in Perenyi's fluid, April 18, shortly after spawning, and 

 subsequently stained in picrocarminate of lithium. X 750. 



" 15. Tangential section near the micropyle. X 112. 



" 15 a . Radial section of an egg 37 mm. in diameter. X 750. 



" 16. Radial section of an egg 0.33 mm. in diameter. X 750. 



" 17. Radial section of an egg 0.37 mm. in diameter. X 750. 



" 18-22. Radial sections through the micropyles of eggs, about 0.4 mm. in diam- 

 eter. In Figs. 20 and 21 the micropyle is cut obliquely. X 750. 



" 20 is from an ovary hardened April 4, i. e. some time before spawning. 



