No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 621 
with the terminal branches of the r. maxillaris superior trige- 
mini, and sends branches along the ventral and along the 
dorsal surface of the premaxillary, one branch of the nerve 
being traced into one of the large teeth of that bone. 
6. Har, Nervus Acusticus, and Nervus Lineae Lateralis Vagi. 
a. Far. 
In 14mm. larvae of Amia the ear (Fig. 57, Pl. XXXV, of 
adult ear) already shows the well-known divisions of the teleos- 
tean ear. The utricular chamber is large, and has a central, an 
anterior, a posterior, and a vertical portion. The two former, 
together, are the utriculus proper, the two latter the sinus 
utriculi posterior and sinus utriculi superior respectively of 
Wiedersheim’s figures (No. 128, p. 351). The utriculus and 
the sinus posterior lie in vertical planes approximately at right 
angles to each other, and at 45° to a vertical longitudinal plane 
of the body. From the anterior, outer end of the utriculus the 
canalis anterior (csa) arises, the lower end of the canal being 
already slightly differentiated as the ampulla anterior (aa). 
The crista acustica amp. ant. extends transversely across the 
lower anterior wall of this ampulla. 
Immediately proximal to the ampulla anterior, from the outer 
side of the utriculus, the canalis externus (cse) arises, running 
at first almost directly backward, and then turning sharply 
inward and forward, against the anterior surface of the sinus 
posterior, to join the lateral surface of the central portion of 
the utricular chamber, that is, the posterior portion of the 
utriculus proper. The ampulla externa (ae) is slightly indi- 
cated, the crista acustica amp. ext. forming a transverse, ver- 
tical, ridge-like projection at the boundary line between it and 
the canal. The crista lies nearly in the middle of the lateral 
portion of the canal. 
The sinus posterior runs outward and backward at a little 
more than 45° to the axis of the body, and lies close against 
the inner and posterior wall of the posterior portion of the 
canalis externus. From its outer end the canalis posterior 
(csp) arises, the ampulla posterior (af) being slightly indicated 
