374 WHEELER. 
DESCRIPTION OF PLATE XV. 
Blatta germanica. 
Fic. 1. Piece of chorion from lateral face of odthecai egg. 
Fic. 2. Piece of chorion from micropylar area with micropyles. @, aperture of 
micropyle; 2, tubule. 
Fic. 3. Transverse section through the crista of a capsule. 0, odthecal wall split- 
ting into two laminze, 0! and 0; cv, crystals of calcium oxalate; ef, remains of fol- 
licular epithelium. 
Fic. 4. Longitudinal section of epithelial cap on the germarium pole of the egg. 
ef, follicular epithelium; c#, chorion secreted by the same; a, the point at which the 
chorion widens, showing its lengthened trabeculz; 4, pyriform dilatation of the chorion; 
pr, protoplasm of the Keinhaut, containing numerous bacteria-like corpuscles. 
Fic. 5. A number of cells from the follicular epithelium. a, resting nucleus; 4 
and ¢, nuclei in akinetic division. 
Fic. 6. Longitudinal section of immature ovum I mm. long, being the circum- 
nuclear portion in the centre of the dorsal concavity of the egg; nucleus amoeboid 
just after reaching the surface. , chromatin particles; x, layer of small yolk bodies 
just beneath the epithelium. 
Fic. 7. Same section of an egg 2mm.long. Nucleus emarginate on outer surface, 
giving off the maturation sphere 4; y, small yolk bodies under the epithelium. 
Fic. 8. Section at right angles to that in Fig. 7, of a nucleus in the same stage. 
6, cavity into which the maturation spheres fitted; #72, paranucleolus. 
Fic. 9. Nucleus in the same stage; fz, paranucleolus. Egg 2 mm. long; section 
in the same plane as Fig. 7. 
Fic. 10. Longitudinal section of median dorsal surface of an egg 2.5 mm. long. 
Particles of chromatin aggregating into a somewhat stellate central mass. 
Fic. 11. Longitudinal section corresponding to Fig. 10 of an egg somewhat older, 
2.8 mm. long. A delicate wall encloses the particles of chromatin. ; 
Fic. 12. First polar spindle in the metakinetic stage. Egg mature. 
Fic. 13. First polar spindle in anaphasis. Egg mature. 
Fic. 14. Median longitudinal section through the dorsal surface of an oédthecal 
egg 4 to 6 hours old. /g/, first polar globule; «, second polar spindle in metakinesis. 
Fic. 15. Longitudinal section through both polar globules, 3 to 4 hours older 
than egg represented in Fig. 14. 
Fic. 16. Surface view of the median dorsal portion of an odthecal egg about 10 
hours old. fg? fg, polar globules; 9? fz, female pronucleus (out of focus). 
Fic. 17. Median longitudinal section of dorsal portion of an oGthecal egg. a, 
dorsal contour; @ fz, female pronucleus just after leaving the polar globules. 
Fic. 18, Longitudinal section of circumnuclear region, from near the middle of 
the homogeneous yolk, with female pronucleus. The arrow in this and the following 
figures points in the direction of the cephalo-caudal axis of the egg. 
Fic. 19. Longitudinal section of circumnuclear portion of egg, one-third the length 
of the egg from the cephalic pole. a@, dorsal contour; 9 fz, female pronucleus; 
& px, male pronucleus. 
Fic. 20. Longitudinal section of circumnuclear area from middle of homogeneous 
yolk. @ fx and P gx, male and female pronuclei conjugating. 
Fic. 21. Longitudinal section of circumnuclear area from the middle of the front 
portion of the homogeneous yolk. Cleavage nucleus. 
Fic, 22, Cleavage nucleus preparing to divide. cf, cytoplasm. 
