622 ALLIS. [VoEn.AXie 
at its lower end, and containing, as a transverse ridge across 
its lower surface, the crista acustica amp. post. 
The sinus superior arises from the central portion of the 
utricular chamber, median to the opening of the canalis 
externus, runs directly upward, and receives at its upper end 
the median, upper ends of the anterior and posterior canals. 
The sacculus (sc) begins immediately under the central por- 
tion of the utricular chamber, connected directly with the latter 
by a large opening without the intervention of what could be 
properly called a canalis utriculo-saccularis. The front wall of 
the sacculus is nearly vertical, and lies on the level of the ante- 
rior edge of the opening connecting it with the utriculus. 
Posteriorly, on the contrary, the sacculus extends directly 
backward a considerable distance, at first immediately under 
the sinus posterior, and then immediately below but median to 
that sinus. Its upper wall lies close to the ventral wall of the 
utriculus, and there is, as yet, no marked constriction indicating 
that this portion is the future lagena. On the inner and upper 
wall of this portion, immediately behind the posterior edge of 
the opening connecting the sacculus with the utriculus, is the 
large papilla acustica lagenae, and immediately above it, in the 
ventral and median wall of the sinus utriculi posterior, the 
smaller macula fundi utriculi, or macula acustica neglecta, 
whichever it may be. From Wiedersheim’s description and 
figures these two maculae seem to occupy exactly the same 
position in fishes and reptiles, and to be apparently identical 
(No. 128, p. 347). In Amia the organ is connected by a line 
of thickened epithelium with the papilla lagenae. 
The macula acustica sacculi lies in the inner and anterior 
wall of the sacculus, and the macula acustica utriculi in the 
ventral and slightly lateral wall of the utriculus in front of the 
opening between the utriculus and sacculus. 
In the adult, as the figure shows, the main divisions of the 
ear differ but little from those of larvae. The cristae and 
maculae acusticae have, however, acquired somewhat different 
positions, but no special description of them seems necessary. 
Neither in the adult nor in any of the larvae did I find any 
satisfactory indication of a ductus or saccus endolymphaticus. 
