AMPHIOXUS LANCEOLATUS. 
405 
nerve-root and a portion of a group of anterior nerve-roots. The small 
lymph-space to the left of the neural crest appears to be part of one of a 
series (alternately right and left) not in continuity with those situate below 
the nerve-roots. The lymph-space below the posterior nerve-root on the 
right, and that below the anterior nerve-root on the left, are parts of corre- 
sponding spaces lying asymmetrically on each side of the skeletal tissue of 
the notochord-sheath and nerve-tube. The relation of the anterior nerve- 
fibres to the deep layer of the myotome is seen on the left side, but probably 
the correct and undistorted relation of these parts is not quite exactly ascer- 
tained (see Rohde, 17). The division of the more ventral portion of the 
myotomes into two groups of fibres, separated by delicate connective fascia, is 
prominently shown. 
The continuity of the gelatinous layer of the cutis between the ventral 
epithelium and the transverse muscle, and the consequent absence of “ventral 
cauals,” is prominently shown. 
The median artery of the endostyle is not drawn. This is an omission 
which is rectified by the series of sections in PI. XXXVI B, Pigs. 4 to 9. 
PLATE XXXVI A. 
Pig. 1. — Portion of a section through the notochord and adjacent region of 
Amphioxus. The specimen had been stained with logwood solution. Some 
of the structures shown are named in full on the drawing. 
The letters have the following signification : — a. Artifact space, produced 
by the shrinking and tearing of muscular fibres from their attachment to the 
muscle fascia, 6. Left myoskeletal lymph-space, between the fascia of the 
muscle of the myotome and the skeletal sheath of the notochord. Whether 
this space is opened out by the action of reagents, or is in its natural condi- 
tion, is uncertain. In either case it represents the similarly situated space of 
Pig. 7, which represents an early larval condition, c. Similar space of the 
right side. d. Upper or para-neural portion of the myoskeletal lvmph-space, 
which is shown by other sections to be in continuity with 6. It contains a 
clot. e. Similar space of the right side, elsewhere in continuity with c. 
f. One of the “godets” of Moreau, or dorsal tubercles of the notochordal 
tissue, g. Artifact space caused by the shrinking of the notochordal tissue 
from its connective-tissue sheath. h. Dorsal canal of the notochord, 
with nuclei and trabeculae, i. Veutral canal of the notochord, k. Thin 
connective-tissue septum (fascia), separating the inner from the outer group 
of muscle-fibres of the myotome. 1. Ventrally placed nuclei of the proper 
notochordal tissue, x. Peculiar granular tract of the connective-tissue sheath 
of the notochord, lying above the plane of adhesion of the pharynx, y. Simi- 
lar but smaller tract of granular-looking tissue at the opposite face of the 
notochord. 
