CRANIAL NERVES OF SIREN LACERTINA 277 
fibrous tissue passes and encircling the eye, is attached to the 
antorbital process.’’ . If this were true it is easy to see that any 
movement of the antorbital cartilage might affect the position of 
the eyeball. The writer finds a ligamentous band extending 
from the postorbital cartilage over the dorsal border of the eye- 
ball, but not directly attached to the antorbital. It is possible, 
however, that movements of the antorbital through its attach- 
ment to the subdermal connective tissue may modify the position 
of the eyeball. 
That in both Amphiuma and Siren there is an antorbital pro- 
cess, with which are connected two muscles obviously homologous 
in the two species, both innervated in each species by a twig of 
the pterygoid branch of the ramus mandibularis V, is a fact 
of considerable importance. From position and innervation it 
may be concluded that these antorbital muscles are derivatives 
of the anterior portion of the pterygoid muscle. That these 
antorbital muscles in Amphiuma and Siren correspond to the 
retractor and levator bulbi muscles in other Amphibia is not prob- 
able, in the light of present knowledge. In Spelerpes (Bowers) 
and in Triton (Coghill) the retractor bulbi is innervated by the 
abducens nerve. In Amblystoma (Coghill) it is innervated by 
the same nerve and the levator bulbi by fibers derived from the 
abducens and the ophthalmicus profundus V. In Salamandra 
(von Plessen and Rabinovicz) the retractor bulbi is said to re- 
ceive a twig from the oculomotor nerve. In the Anura (frog, 
Gaupp, ’99) the retractor bulbi is innervated by the abducens, 
and the levator bulbi by a branch of the ramus maxillaris 
superior. 
4. The ramus ophthalmicus profundus V 
Wilder’s (’91, p. 673) statement that the trigeminal trunks, 
together with the dorsal lateral line trunk of the facial nerve, 
after leaving their respective ganglia ‘‘pass into the same opening 
in the cranial wall’’ is correct but misleading. On leaving the 
gangha the nerves in question pass into the narrowed anterior 
extension of the hollow in which the fused ganglia are situated. 
From this through a common opening the ramus mandibularis 
JOURNAL OF MORPHOLOGY, VOL. 24, NO. 2 
