180 J. B. Johnston 
lost. This nerve, which seems to have no ventral ramus, is the 
first to curve round the ventral and lateral surface of the lateral 
line nerve. Fig. 13 shows a part of its course. 
Spinal ventral 1 arises in 459, passes through the ceranium at 
450, turns laterad and ventrad, goes ventral to the cardinal vein 
between it and the vagus trunk, gains the lateral surface of the 
cardinal and in 453 meets and fuses with the ventral ramus of 
sp.ven.2. Fig. 13. 
Spinal ventral 2 arises by small bundles in nearly every sec- 
tion from 470 to 452 and is the largest ventral nerve in Ammocoetes. 
The bundles unite into a common root which inclines forward and 
passes dorsal to the cardinal vein (Fig. 14). 
At 462 it divides into dorsal and ventral rami. The dorsal 
ramus goes upward and forward past the lateral line nerve, from 
which it is separated by a blood space and a strong septum, goes 
dorso-cephalad between the muscles and the eranium, and forward 
over the auditory capsule, grows smaller and becomes diffieult to 
follow at 389. Two other smaller rami arise from the crotch be- 
tween the dorsal and ventral rami and supply the dorsal part of the 
two next anterior muscle segments. Thus there are three dorsal 
rami arising close together and supplying the dorsal part of the 
first three myotomes. The two small rami arise just where the 
sp.d.1 erosses the chief dorsal ramus and there is some indication 
of both these rami getting fibers from this sensory ramus. The 
ventral ramus continues forward and is joined by the sp.ven.1 (453) 
as above noted. It then divides into two branches one of which 
goes forward, the other ventrad. Both run on the inner face of the 
body muscles and divide and are soon lost. 
Spinal dorsal 2 arises at 480, passes through the cranium at 
475 and enters its ganglion beneath the lateral line nerve. The 
ganglion sends a dorsal ramus up past the z.l.l., from which it is 
separated by a wide blood space. No ventral ramus was seen. 
Spinal ventral 3 arises by small rootlets between 494 and 501, 
divides at 482 into dorsal, ventral and a small lateral ramus, all of 
which go somewhat forward and are lost in the body muscles. 
Spinal dorsal 3 arises on the left side by two roots in 505 and 
515. Both pass through the same foramen and unite in a ganglion 
which lies between 505 and 510. The trunk divides into dorsal 
and ventral rami but the fate of the ventral ramus could not be 
made out. 
