No. 3.] MUSCLES AND NERVES IN AMIA CALVA. Ick 
tory pit (o/p) beneath the nasal sack. Sagemehl says of it that 
it consists of from seven to ten loosely connected bundles of 
fibres, between which there is to all appearance no interchange 
of fibres. I find it to consist of three principal bundles, two 
large ones, one on each side of the nerve, united dorsally for 
about one half their length, and a much smaller ventro-median 
one (Fig. 64, Pl. XX XVIII), lying in the open triangular space 
between the ventral ends of the other two. Between the two 
lateral bundles there is dorsally, for one half their length, 
frequent interchange of fibres, and the two bundles break up 
distally into several bundles. Between the smaller ventro- 
median bundle and the lateral ones there is also an inter- 
change of fibres, but it is much less important than that 
between the larger bundles. This median ventral bundle, in 
whole or in part, seems to be the “hitherto undescribed cranial 
nerve’ of Pinkus in Protopterus (No. 88). 
In the adult the ventro-median bundle of the olfactorius is 
distributed, so far as macroscopic observation can show, to the 
nasal epithelium at the extreme anterior end of the nose. In 
embryos such is also its apparent distribution, though I have 
never been able in my preparations to trace it definitely to that 
tissue. During the larger part of its course, in 30 mm. to 
50 mm. specimens, it is easily distinguished from the lateral 
bundles by the presence of the large round cells which Pinkus 
describes in Protopterus. Near the anterior end of the ol- 
factorius, however, these cells disappear, and the fibres into 
which the bundle breaks up cannot be distinguished from the 
other terminal branches of the main nerve. All the fibres 
of the bundle apparently enter the nasal tissue, and neither 
in embryos nor in the adult do I find such a mass of cells 
at the end of the nose as Pinkus describes in Protopterus. 
They may possibly represent in Protopterus a rudimentary 
condition of the intermaxillary gland described by Gage in 
Diemyctylus. 
Between the ventro-median bundle of the olfactorius and the 
lateral bundles there is, in large larvae as in the adult, frequent 
interchange of fibres. Toward the root of the nerve in such 
larvae the large round cells that characterize the bundle dis- 
