248 JouRNAL OF CoMPARATIVE NEUROLOGY. 
PLATE XIV. 
fig. 1. Projection on the horizontal plane of the lateral line canals, their 
nerves and sense organs of the left side. X 28. The scales at the top and bot- 
tom of the plate indicate millimeters divided into quarters. The root portions 
of some other parts of the trigeminus, facialis, glossopharyngeus and vagus 
are indicated in outline, while the lateral line nerves are drawn in black. The 
brain and olfactory and optic nerves are shaded with stipple. The outline of 
the eye is indicated by a dark continuous line, and the origins of the nasal, 
mental and post-mental barblets by heavy dotted lines. The lateral line canals 
are cross-hatched, their organs are indicated as black rings, while the large pit 
organs are indicated as black discs. Thesmall pit organs are not indicated. 
The canal organs and pores are numbered from before backward in each canal 
(the former in Arabic, the latter in Roman numerals), and the boundaries of 
the bones through which the canals pass are indicated by heavy curved lines 
marked by abbreviations of the bones, in capital letters. Regarding the nomen- 
clature of the canals, the supra-orbital canal is regarded as terminating in the 
fifth supra-orbital pore ; the infra-orbital canal terminates at its union with the 
supra-orbital; and the canal running caudad from this point into the trunk is 
the main canal. In this specimen the opercular canal does not communicate 
with the main canal. The relations in two other specimens, in which these 
canals do communicate, are indicated by dotted lines. 
\ 
PLATE XV. 
Fig. 2. Projection of the sensory trigemino-facial roots on the sagittal plane 
as seen from the left side. X 65. The scales at the top and bottom of the plate 
indicate millimeters (measured from the tip of the snout) divided into quarters. 
The outline of the brain is indicated by a heavy continuous line. The communis 
system is indicated by wide cross-hatching, the lateralis system by narrow cross 
hatching and the general cutaneous system by stipple. Ganglion cells belong- 
ing to the communis system are indicated by xX, to the lateralis system by o 
and to the general cutaneous system by +. Superficial origins of the roots 
from the brain are indicated by double transverse lines ; foramena in the skull 
by single transverse lines. 
PLATE XVI. 
Fig. 3. Transection through the head at the level of exit of the optic 
nerve fromits foramen (6 millimeters from the tip of the snout, cf. Fig. 1) & 28. 
In the r. ophthalmicus superficialis V, the r. maxillaris and r. mandibularis the 
relations of the two sensory components are indicated by the lines dividing 
these nerves, the general cutaneous component being dorsal and lateral and the 
communis component ventral and mesial. 
This and the following transverse sections, though apparently from the 
right side, in reality illustrate the left side, the relations having been reversed 
by the projection. 
