520 ALLIS. PVOE aie 
of the rectus externus, behind and below the rectus inferior, 
and below the rectus internus. 
In all other ganoids, both chondrostean and holostean, the 
same arrangement is found ; at least I so interpret the descrip- 
tions given by van Wijhe (No. 129) of the muscles and nerves 
in Acipenser sturio, Polypterus bichir, and Lepidosteus osseus, 
and these three fishes may be assumed to represent all ganoids. 
Schneider says (No. 112, p. 12) that in Acipenser, Scaphirhyn- 
chus, and Amia the inferior branch of the oculomotorius, after 
passing between the rectus superior and rectus externus, con- 
tinues forward in the ‘“‘Kegel”’ formed by the recti muscles. 
This would seem to mean that the oculomotorius runs forward 
above the rectus inferior and rectus internus, but in his Fig. 1, 
showing the arrangement in Acipenser, the nerve passes below 
the rectus inferior, as it does in van Wijhe’s Fig. 3 of the same 
fish. In Amia my work leaves no doubt as to the arrangement ; 
the nerve runs below the two muscles. 
The same arrangement of the nerves and muscles of the eye 
is probably found in all teleosts. The obliquus superior and 
rectus externus are certainly innervated, respectively, by the 
trochlearis and abducens, as in ganoids, and the remaining 
muscles by the oculomotorius, but that this nerve has, in all 
teleosts, the same distribution and the same relation to the 
muscles, as in ganoids, cannot be definitely determined from 
the literature. Most references simply say that the four 
muscles are innervated in the usual or well-known way. In 
Amiurus, where, according to Wright (No. 132, p. 365), the 
inferior branch of the oculomotorius runs over the inferior and 
internal recti, it was found in its usual position wxder those 
muscles in the one specimen that I examined. 
In the Chondropterygii, or Elasmobranchii, a somewhat dif- 
ferent arrangement is found. In these fishes the superior 
portion of the oculomotorius supplies the rectus internus as 
well as the rectus superior, the inferior portion of the nerve 
supplying only the rectus inferior and the obliquus inferior. 
In Holocephala the rectus internus arises near the front end 
of the orbit, at some distance from the other recti muscles, 
and the nerve supplying it runs forward above the opticus 
