480 Proceedings of Royal Society of Eclinhurgli. [sess. 
II. Lcemargus .- — We do not find in Lsemargus the same variation 
in the spinal nerves that is so characteristic of the skate. The 
ventral roots of the first three pass through the cranium, and, as in 
the skate, the first two have no dorsal roots, the first again (a very 
fine nerve) having, apparently, no dorsal branch. The second has 
a dorsal branch coming up through the cranium to the skin. The 
third ventral root (the dorsal root of which passes through the 
vertebral column) has a dorsal branch coming up through the 
cranium to the skin, hut in passing the ganglion on the dorsal root 
it becomes attached to and receives fibres from it. The anatomy 
of all the other spinal nerves examined was of the same character ; 
and, it may be mentioned, this origin of the dorsal branch, principally 
from the ventral root, with fibres from the dorsal root, resembles 
the condition found in man. 
