No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 623 
Why these structures, found so generally in fishes, should be 
wanting in Amia I cannot imagine. I can only suppose that 
my sections were imperfect, so far as the ear is concerned, or 
that the ear not belonging especially to my subject, and but 
little attention having been given to it, I failed to recognize 
the endolymphatic parts of it. The membranous parts of the 
ear were often much collapsed and distorted in my sections, 
but in the adult they seemed perfect. 
Along the median surface of the sinus superior, in the adult, 
there was always a broad band of delicate, strongly pigmented 
tissue, running upward from about where the ductus endo- 
lymphaticus would naturally begin. It was always closely 
attached by its edges to the wall of the sinus, and in that wall 
there was a white line, due apparently to a thickening of the 
tissue of the wall. 
b. Nervus Acusticus. 
The nervus acusticus, in young larvae, arises from the summit 
of the lobus acusticus by three distinct roots, two of them 
often so fused that it is difficult to distinguish them in sec- 
tions. In different specimens they seem, as they issue, to 
have slightly different positions relative to each other. In one 
14mm. specimen, cut in horizontal sections, they were particu- 
larly distinct, one root lying slightly above the other two, 
which two were, however, cut in the same section. They all 
had their apparent origins immediately below the utriculus 
and immediately in front of the sacculus, and each of them 
entered a definite part of the large irregular acoustic ganglion. 
The upper root, which is the main posterior root of the nervus, 
gave origin to the ramus cochlearis, which turned directly back- 
ward internal to the sacculus, supplied at once the macula 
sacculi, then the papilla lagenae and macula fundi utriculi by 
branches arising close together, and then, turning outward and 
backward above the lagena, between it and the ventral surface 
of the sinus utriculi posterior, and always separating into two 
terminal branches, supplied the crista ampullae posterioris. 
The other two roots together formed the main anterior root 
of the nervus and, together, gave origin to the ramus vestibu- 
