No. 3.]| MUSCLES AND NERVES I[N AMIA CALVA. 513 
ever, found near the median ventral surface of the olfactorius 
indicating a partial separation into two bundles. 
Wiedersheim (No. 128, p. 256) in a figure of the brain of 
Rana esculenta shows two roots of the olfactorius, but gives no 
special description of them in the text. Lee (No. 72) describes 
and figures a similar arrangement in Spelerpes fuscus, and 
states, on the authority of Miklucho Maclay and von Rohon, 
that the olfactorius is frequently found double in selachians. 
Whether the two roots so described are the two main portions 
of the root in Amia, or one of them the small root “‘n”’ and the 
other the main double root, I am unable to judge. 
No ganglion cells other than those described in the ventro- 
median bundle were found in any part of the olfactorius in any 
of the specimens examined. Whether these cells in the adult 
and the ganglionic mass in young larvae are the olfactory gang- 
lion of Beard (No. 9, pp. 878 and 884) or not I am unable to 
state, not having seen his complete and later work. I am also 
unable to judge whether they are, or are not, a remnant of the 
ganglionic mass from which the nervus olfactorius is said by 
Holm (No. 58) and Chiarugi (No. 18) to develop, my investiga- 
tions being confined to embryos already too advanced for the 
purpose. 
The olfactory canal in Amia (o/c) is considered by Sagemehl 
(No. 104, p. 217), it seems to me erroneously, as simply an 
anterior extension of the cranial cavity. It is separated from 
the anterior end of the orbit by a thin wall of cartilage through 
which, at about the middle of the canal, from its side and bottom, 
there is a large opening (onfn, Fig. 25, Pl. XXV) leading into 
the extreme front end of the upper part of the orbit. This open- 
ing in Amia seems to have entirely escaped Sagemehl’s notice, 
although in Lepidosteus, in the Characinidae, and in teleosts in 
general it and its relation to the nervus olfactorius are described 
at considerable length by him (No. 104, p. 219, and No. 106, pp. 
68 and 72). In Catostomus he did not find it, and he says of it 
that it has no physiological importance whatever (No. 107, p. 
566). It lies in Amia internal to and under the antorbital 
process, directly above the obliquus superior near its origin, and 
through it a large venous vessel passes from the olfactory pit 
