440 ALLIS. [Vou. XIV. 
(No. 36, p. 96) it is formed by the fusion of several bones, some of 
which are still found separate and independent in certain fishes. 
The canal that traverses the bone or bones was called by 
me in my earlier work (No. 1) the opercular part of the 
operculo-mandibular lateral canal. For the latter canal I now 
propose the name preoperculo-mandibular canal, and for its two 
parts the names preopercular canal and mandibular canal. The 
reason is evident, the canal always traversing or lying in the 
preoperculum, and not the operculum. That a double name 
for the whole canal, or, if a single name is used, two separate 
names for the two parts of the canal, is necessary, is evident 
from the fact that the canal develops as two wholly separate 
and independent parts, which may or may not later unite to 
form a single canal (No. I, p. 529). 
For this entire canal, Ewart (No. 14), who takes exception 
to the name adopted by me in my earlier work, has proposed 
the name hyomandibular canai, this name being based on the 
name of the nerve that innervates the organs of the line. In 
sharks other than Laemargus (No. 14, Pl. II, Fig. 2) he, how- 
ever, gives the name hyomandibular more particularly to what 
is apparently the homologue of the preopercular part only of 
the canal in Amia; calling what is apparently the homologue 
of the remaining, lower and distal part of the canal of Amia the 
mandibular canal, as I did in Amia. Collinge (Nos. 11, 12) 
adopts the name hyomandibular for the entire canal, but uses 
that name interchangeably with operculo-mandibular in the 
fishes described by him. Platt (No. 29, p. 494) adopts the 
name hyomandibular, as proposed by Ewart, but apparently 
applies it in Necturus, as applied by Ewart in sharks in gen- 
eral, to the preopercular part only of the canal of Amia; stating, 
moreover, that the line of sense organs so designated in Nec- 
turus is the homologue of the operculo-mandibular line of my 
descriptions of Amia, that is, of the entire line. The only other 
supposition possible, and perhaps the correct one, is that the 
so-called mandibular line of Necturus is the homologue of the 
cheek and mandibular lines of pit organs of Amia. 
The hyomandibular line of Platt, in Necturus, is said by 
her to be. innervated by the hyomandibularis facialis, the ven- 
