338 
Aufsätze. 
Nachdruck verboten. 
On the Anatomy and Phylogenetie Position of Polypterus. 
By H. B. Portarp B.A. B.Sc., Scholar of Ch. Ch. Oxford. 
From the Anatomical Laboratory at Freiburg i. B. 
(Preliminary Communication.) 
With two figures. 
1) Auditory Organ. The auditory organ of Polypterus lies 
laterally to and on a level with the hinder part of the brain. Its 
cavity is considerably larger than the brain cavity in that region and, 
the two are not completely cut off by cartilage. The membranous la- 
byrinth shows the usual structures with the exception of the ductus 
endolymphaticus which, with the material at my disposal, I failed to 
find. The semicircular canals are long and somewhat slender, and the 
external horizontal shows this peculiarity that it extends far round 
internally, where it has a special cartilaginous canal of its own, and 
then passes outward to open on the outside of the utriculus. The 
utriculus has become triradiate in form and the recessus utriculi is 
small. The utriculus opens almost directly into the sacculus which 
is immense. It does not lie as in the other bony Ganoids below the 
level of the rest of the ear but its upper surface is almost on a level 
with the highest point of the semicircular canal. The long course of 
the external horizontal semicircular canal is no doubt due to the great 
expansion of the sacculus. Pigment occurs in radiating lines on the 
sacculus and as a curious triangular patch on the inner side of the 
utriculus. Two large otoliths are present in the sacculus, the posterior 
being the larger, and the organ shows, correspondingly, slight traces of 
a division. In the recessus utriculi is a small otolith. 
The auditory nerve divides immediately into an anterior and po- 
sterior branch. The posterior immediately divides giving off the nerve 
supply to the large macula on which rests the posterior otolith of the 
sacculus, a ramus to the macula neglecta which is situated close to the 
junction of utriculus and sacculus and a branch to the posterior am- 
pulla. The anterior consists practically of two branches one of which 
runs to the macula of the sacculus which lies on its anterior border 
which corresponds to the anterior otolith. The other branch supplies 
the recessus utriculi and the anterior and external ampullae. 
