PROCEEDINGS OF THE NATIONAL MUSEUM. Le. 
| Fig. 10. A late stage in the tormation of the blastodisk. 
ets 11. Preparing to segment. 
12. An early stage in the first segmentation. 
13. Optical section at the completion of the first segmentation. 
14. Surface view of the four blastomeres. 
15. Surface view of the third segmentation furrows. 
16. Optical section of sixteen cells. 
17. Optical section after fourteen hours. 
18. Optical section after twenty-four hours. 
19. Optical section after thirty-two hours. 
20. Diagram ofembryo after sixty-four hours. 
21. Diagram of embryo after seventy-five hours. 
22. Embryo of six and a half days. 
23. Embryo in later stage showing yolk circulation. 
24. This is probably an Atherinops having been procured as late as April 22. 
It measured 54 millimeters. 
25. An Atherinopsis 9 millimeters long. 
26. An Atherinopsis 12 millimeters long. 
27. An Atherinopsis 14 millimeters long. 
Fig. 
WAGE oxen Ve 
. (Destroyed). Young Clevelandia or Lepidogobius taken with a surface net. 
. An older lava of the same. 
. Tail of a larve intermediate between Figs. 1 and 2. 
. Tail of an older larva. 
. Clevelandia longipinnis. 
. Gillichthys y-cauda. 
PLATE XV. 
. Egg of Typhlogobius californiensis undergoing the first cleavage. 
. Micropylar region of an egg of the same species under pressure, Showing the 
margin of the attachment of the outer membrane. 
. An egg forced from the ovary. A very large breathing chamber has been 
formed. Abnormal (?). 
. A portion of the network of the outer membrane remote from the micropyle 
of the egg represented in Fig. 3. 
. Micropylar region of the egg represented in Fig. 3. 
. Adult Typhlogobius, natural size, in the position usually assumed in the 
aquarium. 
. Young Typhlogobius. Xx4%, showing color markings and the eye. 
. Dorsal view of skull of Typhlogobius. x4. 
. Lateral view of same. xX. 
. Ventral view of same. X14. 
. Eye, optic nerves and portion of brain of same, showing the very much elon- 
gate slender optic nerves and the comparatively large lens as compared. 
with the eup of the eye. x 24, from nitrie acid maceration vf a specimen 
13 mm. long, January 29, 1888. 
. Gillichthys mirabilis. 21 millimeters long. 
. A single scale of same more enlarged. 
. Several scales with color cells from the tail of same. 
. Sense organs of the lateral line of a younger specimen of Gillichthys, from 
about the middle of the body. 
. Solitary sense organ of the same from the base of the caudal. 
Proc. N. M. 92 12 
