Nos. 4, 5, 6. Sections through the third groove.

No. 7. Section through the point where the third groove passes into the solid rod of cells.

No. 8. Section through the rod when quite separated from the germinal epithelium.

No. 9. Section very near the termination of the rod.

No. 10. Last section in which any trace of the rod is seen.

Series B. Sections passing through the head-kidney at our third stage. Zeiss C, ocul. 2. Our figures are representations of the following sections of the series, section 1 being the first which passes through the anterior groove of the head-kidney.

No.1Section3.
"2"4.
"3"5.
"4"6.
"5"8.
"6"10.
"7"11.
"8"13.
"9"15.
"10"16.
"11"17.
"12"18.
"13"19.
"14"20.

The Müllerian duct extends through eleven more sections.

The first groove (gr1.) extends to No. 3.

The second groove (gr2.) extends from No. 4 to No. 7.