250 
six spinal nerves of the right side seen from 
the lateral aspect. ‘The two crosses indicate 
the position of the foramen magnum. ‘The 
cranial region is to the right of these, the 
vertebral to the left. The reconstruction is 
from the same series of sections as figures 
23-26, but is not drawn to the same scale. 
The formal shading of the ganglia is omitted 
in the case of the first spinal for the sake of 
clearness. The roots of most of the spinal 
nerves lie internal to the ganglia and there- 
fore cannot be shown. Their places of 
origin, however, are indicated by the oval 
dotted areas. 
Fig. 28. Transverse section through the fore-brain to 
illustrate the asymmetry of this part of the 
brain. The dotted line indicates the mid- 
vertical plane. Most of the brain therefore 
here lies to the right. Note the fibres col- 
lecting at the base of each bulbus olfactorius. 
These ultimately form the olfactory nerves. 
Drawn with the camera, Zeiss aa. oc.4. 
PLATE, X. 
Fig. 29. Plaice split up the middle from below into two 
halves and spread out to show both sides of 
the sensory canal system. x #. The anterior 
extremity of the dorsal fin is not shown. 
The shading indicates the innervation of the 
sensory canals. Swpraorbital canals, cross. 
_ hatched (R. ophthalmicus superficialis, vii.) ; 
Infraorbital canals, dotted (R.  buccalis, 
vil.); Hyomandibular canals, shaded (R. 
mandibularis externus, vii.) ; Lateral canals, . 
