Eioenmann. — Egg Membranes. 



ABBREVIATIONS. 



cp. Blood corpuscles. /?rj. z c/. Intercellular ridges. 



fil. Filaments of Fundulus. 



fil. vt. Filaments of vitellus. 



gran. Granulosa. 



m py. Micropyle. 



m py. cl. Micropylar cell. 



til. gran. Nucleus of granulosa cell. 



til. in py. Nucleus of micropylar cell. 



po. can. Pore-canals of the zona radiata. z.r.' Zona radiata externa. 



pr. c. Rivet-shaped processes of zona. z. r." Zona radiata interna. 



PLATE II. 



Figures 23, 24, and 25 are on Plate III.; Figures 26-32 are from Perca. 



Fig. 26. Radial section through the micropyle of an ovarian egg from Perca killed 



in February. X 750. 

 " 26 B . Section through the micropyle (?) of an egg of Perca. X 750. 

 " 27-32. A series of sections tangential to the surface of an egg of Perca 1 mm. 



in diameter at a point somewhat to the right of the micropyle. The 



portion of the sections to the right if the micropylar region lies deeper 



than the portion to the left. In 

 " 27, the cells lying to the right of the region of the micropyle are crowded, and 



have a curved band-like arrangement. The cells which contain dark 



points and lie farther to the right are from the central portion of the 



section, and are therefore cut across deeper than the others. In the 



second section, 

 " 28, only the deeper, filamentous prolongations of these cells are seen. In 

 " 28, 29, a median pit can be traced through the centre of the column of cells 



which occupies the micropylar region. In 

 " 30 the nucleus of the enlarged micropylar cell (nl. mpy.) is seen. In 

 " 31 is seen the enlarged mouth of the mycropyle (m py.) and a few cells which 



lie somewhat higher and to the left of it. 

 " 32 is a section through the zona radiata and micropylar canal. 



This egg was preserved February 15 in Perenyi's fluid, and was stained 



with Czoker's alum-cochineal. X 425. 

 " 33. Radial section of an ovarian egg of Mnrone americana 0.28 mm. in diam- 

 eter. Hardened in chromic acid February 25, and stained with picro- 



carminate of lithium. X 750. 

 " 34. Radial section of a larger egg (0.4 mm. in diameter) of Morone americana 



from the same series of sections as that of Fig. 33. X 750. 

 " 38. Radial section through the micropyle of an egg of Notemigonus chryso- 



leucus 0.63 mm. in diameter. Ovary of May 5, killed in Perenyi's 



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

 " 45. Radial section through the egg of Amiurus catus. Ovary of May 9, killed 



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



The radial markings have been accidentally omitted and fil. vl. placed 



for./?/, vt. 



