On the Structure of the Excretory Organs of Amphioxus. Part 2.—The ...

204 EDAVIIS: S. GOODRICH.
FIG. 1.2.—Next section to that drawn in fig. 10.
FIGS. 13 and 14.—Two consecutive sections through the ventral end
of fcho anterior limb of a nephridial canal. Cam. L. TV oil-imm., oc. 3.
PLATE 13.
FIGS. 15. 16, and 17.—Three consecutive sections, parallel to a gillliar,
through the extremity of a diverticulmn of the nephridial canal.
Cam. Z. 2 mm. ap. oil-imm., oc. 12. In figs. 15 and 16 the solenocyte
tubes are cut in the thickness of the wall of the canal.
FIG. 18.—Section across the ends of two adjacent nephridial diver -
ticula. The bases of solenocyte tubes are clearly seen embedded in the
cytoplasmic wall. Cam. Z. 2 mm. ap. oil-imm., oc'18.
FIG. 19.—Longitudinal section cutting the surface of a neplrridiuin.
Cam. L. -j\,- oil-imm., oc. 3.
FIG. 20.—View of the portion of the next section corresponding to
the left-hand region of fig. 19.
FIG. 21.—Similar section of another nephridium.
FIG. 22.—Diagram to illustrate the direction of the sections drawn in
figs. 5, 9, 10, 13, 15, and 19.
PLATE 14.
FIG. 23.—Section across the top of one primary and two secondary
gill-bars, showing the position of the solenocyte chambers (ch.), and of
the blood-vessels. The position of the external pore at a lower level is
indicated by a cross X.
FIG. 24. —Transverse section of a larva, passing through the mouth,
and opening of Hatschek's nephridium. Cam. Z. D., oc. 3.
FIG. 25.—Transverse section farther forward passing just beyond the
anterior end of Hatschek's nephridium, where the cavity in which it lies
opens into the first myoccele.
FIG. 26.—More enlarged view of a portion of the next section,
showing the solenocyte tubes in a cavity continuous with the first
myoccele.
FIG. 27.—Anterior end of an adult Amphioxus, ventral view. The
buccal cavity has been opened up by ratting along the mid-ventral line
Hatschek's nephridium is seen on the left side of the notocliord.