No. 3. Section through the Müllerian duct, just posterior to the persistent opening.
Nos. 4 and 5. Remains of the ridges, which at an earlier stage connected the first and second grooves, are seen passing from the Müllerian duct to the peritoneal epithelium.
No. 6. Rudiment of the second groove (gr2.) of the head-kidney.
Between 6 and 7 is a considerable interval.
No. 7. All traces of this groove (gr2.) have vanished, and the Müllerian duct is quite disconnected from the epithelium.
No. 8. Rudiment of the third groove (gr3.).
No. 9. Müllerian duct quite free in the space between the peritoneal epithelium and the Wolffian duct, in which condition it extends until near its termination. Between Nos. 9 and 10 is an interval of eight sections.
No. 10. The penultimate section, in which the Müllerian duct is seen. A lumen cannot be clearly made out.
No. 11. The last section in which any trace of the Müllerian duct is visible. No line of demarcation can be seen separating the solid end of the Müllerian duct from the ventral wall of the Wolffian duct.
Figs. E. and F. Sections through the glomerulus of the head-kidney from an embryo prior to the appearance of the head-kidney. Zeiss B, ocul. 2. A comparison of the two figures shows the variation in the thickness of the stalk of the glomerulus. E. Section anterior to the foremost Malpighian body. F. Section through both the glomerulus of the head-kidney and that of a Malpighian body. The two are seen to be connected.