GILL] LIFE HISTORIES OF TOADFISHES 423 
Alosa sardina’’), reference is made to the spines at the front of the 
pelvis and the flatness of the belly which are believed to especially 
fit the fish for penetrating into the sand. The form and sculpture 
of the head and the color of the eyes are adapted to assimilation 
to its environments and concealment. The vermiform extension of 
the intralabial valve serves as a bait. How these structures were 
used was the subject of speculation. Now Dr. Facciola may speak 
for himself (pp. 22-28). 
At this time I fortunately had a live individual. It stayed at the 
bottom of the basin, keeping the pectoral and ventral fins spread 
out, while the others were lowered. The mouth was opened to 
the extent of scarcely two millimeters, and the opercles were closed. 
The lower jaw moved very slightly backwards and forwards, the 
extension not amounting to more than one millimeter. But inside 
the mouth and within the jaw was seen a more energetic movement, 
like that of a kind of valve which was raised and lowered; this 
belonged to the transverse membrane which is attached to the inner 
border of the lower jaw and gives rise at the middle to a linguiform 
extension. This participated in the movement and inclined to pro- 
ject out of the mouth. Thus there seemed to me to be no doubt 
that the sublingual membrane assumed the functions of the lower 
jaw which moved almost insensibly. I held the lower jaw apart 
by means of a pair of pincers to see what would happen under the 
circumstances. Then the sublingual membrane stopped beating 
and the hyoid was raised and lowered, but so regularly as to 
- suggest that these movements were excited by the exceptional state 
in which the fish was placed through the forced abduction of the 
lower jaw. When the fish was free again, and I observed more 
carefully the movements of the transverse membrane, I became 
convinced that these movements were passive ones and produced 
by a quantity of water that comes between the membrane and the 
underlying hyoid and were impelled by the action of the latter bone. 
This easily explained the inertness of the membrane when the 
mouth was held open, the reason being that. under the circum- 
stances the hyoid is moved backwards and its upper border no 
longér corresponds to the lower part of the membrane. It is to 
be noted that the tongue does not advance much in front of the 
hyoid and forms with the latter a single border regularly convex 
and corresponding with the form and disposition of the transverse 
*This membrane was well described by Rondelet, questioned by Willughby, 
and again confirmed by Cuvier and Valenciennes.—Facciola. 
