Eigenmann. — Egg Membranes. 



ABBREVIATIONS. 



Intercellular ridges. 

 Space below micropyle. 

 Tubules of the capsular mem- 

 brane in Perca. 

 Theca folliculi. 

 Vacuole. 

 Yolk. 



Zona radiata, 

 Zona radiata externa. 

 Zona radiata interna. 



Fig. 23. Radial section of an egg of Perca in October, 0.5 mm. in diameter. The 

 ovary was hardened in 0.25 per cent chromic acid, and subsequently 

 stained with Czoker's alum-cochineal. X 750. 



Radial section through the micropyle of an egg of Perca. The ovary was 

 preserved in Perenyi's fluid, May 9, and stained in carminate of 

 lithium. X 425. The definite line at the outer margin of the zona 

 radiata should have been omitted. 



Radial section of an egg of Perca, 0.9 mm. in diameter. From an ovary 

 hardened in February. X 425. 



Figures 26-34 are on Plate II. 



Radial section through the micropyle of an egg of Esox, 0.47 mm. in 

 diameter. Ovary of February 23 killed in chromic-osmic-acetic mix- 

 ture, and stained with picrocarminate of lithium. X 750. 



Radial section through the micropyle of an egg of Esox, 0.94 mm. in 

 diameter, from the same series represented in Fig. 35. X 750. 



Radial section of an egg of Esox, 1.5 mm. in diameter, from the same 

 series. X 750. 



Radial section of an egg of Clupea vernalis, 0.54 mm. in diameter. Pre- 

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

 X515. 



Radial section through the egg of Cyclogaster liparis, 0.7 mm. in diameter. 

 Ovary of April 26 preserved in Perenyi's fluid, and stained with picro- 

 carminate of lithium. X515. 



Radial section through the egg of Cyclogaster liparis, from an ovary of 

 May 7 preserved in Perenyi's fluid, and stained with picrocarminate 

 of lithium. X 515. 

 42, 43, and 44. Radial sections through the micropyles of three eggs of Cyclo- 

 gaster, about 0.25 mm. in diameter. Ovary of May 7 preserved in 

 Perenyi's fluid. X 515. 



24. 



25. 



35. 



36. 



37. 



40. 



41. 



