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

STRUCTURE OP THE EXCRETORY ORGANS OP AMPHIOXUS. 205
FIG. 28.—Small portion of a transverse section of the head, showing
Hatschek's nepliridium. Cam. L. oil-imm., oc. 3.
FIG. 29.—Similar view of a larva (the same as that in fig. 24, from
Helgoland, with about thirteen gill-slits). Cam. L T\- oil-imm., oc. 3.
FIG. 30.—Portion of a longitudinal section of a larva, showing a
nephridium opening behind the last open gill-slit. Cam. Z. 2 mm. ap.
oil-imm., oc. 4.
FIG. 31.—Portion of a longitudinal section of a larva, showing the
fan-like group of solenocytes on the aorta. Cam. Z. 2 mm. ap. oil-imm.,
oc. 4.
PJLATE 15.
FTG. 32.—Left side view of a larva, drawn from living and preserved
specimens.
FIG. 33.—Left side view of the anterior region of a slightly older
larva on a larger scale, from living and preserved specimens. The cilia
are not indicated.
FIG. 34.—Left side view of the posterior branchial region of a larva,
showing the disposition of the solenocytes. From the living.
Fin. 35.—Ventral view of a region of a larva, showing the last open
gill-slit, and two more posterior nephridia. From the living.
FIG. 36.—Ventral view of two posterior gill-slits of a living larva.
FIG. 37 —Solenocytes from Hatschek's nephridium in the larva.
FIG. 38.—Optical section of Hatschek's nephridium in the larva.
From the living.
FIG. 39.—Ventral view of a nephridium showing its opening just
within the margin of a posterior gill-slit in a larva. Solenocytes cut
short.
PLATE 16.
FIG. 40.—Left side view of a single nephridium in a larva. From
the living.
FIG. 41.—Portion of a transverse section of a larva, passing through
the nephridiopore. Cam. Z. 2 mm. ap. oil-imm., oe. 4.
FIGS. 42, 43, and 44.—Portions of three transverse sections of the
head of the adult, showing Hatschek's nephridium. In front of the
ciliated pit (fig. 42), at the level of the ciliated pit (fig. 43), and behind
it (fig. 44).
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