165 
of its nerves with the other cranial nerves, it has so far 
been found impossible to devise really satisfactory experi- 
ments. F. 8S. Lee, the latest investigator of the function 
of the lateral line organs, concludes that they are con- 
nected with the sense of pressure or equilibration, and 
even if this be not the case, there is some reason to doubt 
whether the latter can be located in the semi-circular 
canals as in higher vertebrates. 
The Lateral Canal (/at. c.)—This canal, in part the 
“lateral line’’ of systematists, is supported during the 
greater part of its length by modified scales. Arrived at 
the region of the shoulder girdle it tunnels through the 
post-temporal, and then for a short distance has no bony 
support. It now enters a chain of ossicles, undoubtedly 
metamorphosed scales, called supratemporal ossicles or 
extrascapule. The last or most posterior supratemporal 
is attached to the dorsal surface of the pterotic at the 
region of the posterior depression shown in fig. 1, and is 
larger than any of the others. It consists of 2 parts, one 
running longitudinally in a curve for the * lateral line,” 
and the other transversely and somewhat forwards for the 
terminal portion of the supratemporal canal. Whilst in 
this ossicle the lateral canal on the ocular side anastomoses 
with the posterior extremity of the infraorbital canal, and 
then turns abruptly upwards almost at right-angles, and 
afterwards forwards, the latter or anterior portion of the 
canal being called by some authors the supratemporal 
canal (s. ¢. ¢.). The last supratemporal ossicle of the 
Plaice therefore corresponds to the second, third and 
fourth of the Cod fused together. In one Plaice examined 
there were in all 13 supratemporal ossicles on the ocular 
side, as described by Traquair, but the recurrent portion 
of the canal, usually present at its anterior extremity in 
the adult (see figs. 23 and 29) was absent in this specimen, 
