108 Cc. H. DANFORTH 
homologies seemed clear. Elsewhere I have endeavored to select 
terms which seemed least likely to admit of ambiguity. In the 
following account muscles are described as taking origin from 
that attachment which would seem ordinarily to be the less mov- 
able, and as being inserted on the more movable one. For this 
reason, in a few cases, the descriptions here are not quite parallel 
with those of Vetter for Acipenser. The action of the several 
muscles has been determined only by inference and may very 
frequently be inadequately, or even somewhat inaccurately, 
stated, since in contracting every muscle works with or against 
a number of ill-defined forces which tend to modify its proper 
action, often to a marked degree. 
The statements regarding nerve supply are based on dissections 
and study of serial sections. The nerves are referred to by the 
same names as are employed by van Wijhe (’82) whenever the 
nerve in question is described by that writer. 
In describing the blood supply the papers of Allis (11) and 
the present writer (12) are followed in so far as the arteries are 
concerned. Since no adequate account of the veins has yet been 
published, references to these vessels are necessarily less complete. 
Il. EYE MUSCLES 
The muscles of the eye and the arrangement of structures in 
the orbit conform essentially to the ganoid type worked out by 
Allis (97) in his Amia paper. 
The two oblique muscles arise at the anterior Sxirounae of the 
orbit in the angle between the cranial wall and the olfactory 
capsule. Their points of origin, however, are so widely separated 
that the two muscles are practically parallel throughout their 
whole course. The superior oblique arises high up and runs 
diagonally back through the orbit in a nearly horizontal plane 
to its insertion near the median level of the eye and dorsal to 
all the other muscles. The inferior oblique, arising below and 
anterior to the foregoing, crosses the floor of the orbit and is 
inserted on the ventral side of the eye capsule. The four rectus 
muscles are fused proximally in a common short tendon of origin 
