276 H. W. NORRIS 
ternal nostril. Fischer (’64) and later Wilder (’91) noticed the 
relation of the posterior of these two small muscles to the lateral 
valvular fold of the postnaris, but neither detected the other 
muscle, nor, apparently, determined the insertion of the retractor 
muscle on the antorbital cartilage. Anton (’11) recognizes in 
Siren a mechanism for the closing of the choana, but seems to 
overlook the presence of the antorbital muscles, and any relation 
of the cartilage to the regulation of the size of the opening. 
As the antorbital cartilage in Siren has no close relation to the 
eyeball it is hardly appropriate to designate its muscles as bulbar 
muscles. They are here termed retractor and levator antorbi- 
talis muscles, as they should have been designated in Amphiuma. 
Their origin, insertion and innervation in Siren point to their 
complete homology with the muscles in Amphiuma termed re- 
tractor and levator bulbi. They evidently do not correspond to 
any of the muscles described by Bruner (01’) in the Urodela and 
Anura, which are concerned in the regulation of the size of the 
opening of the external nares. 
Vaillant (’63) in describing the muscles of the head in Siren 
mentions ‘‘]’ abducteur de la machoire superieure,’’ a small mus- 
cle inserted in part upon a small bone believed by Cuvier to be 
a maxilla. The writer has not had access to the paper on Siren 
by Cuvier, but has consulted the reproduction of his figures by 
Hoffmann (’78). Fischer and Wilder have not been Sable to find 
either the muscle mentioned by Cuvier and Vaillant or the small 
bone upon which it was said to be inserted. Parker (’82, p. 188) 
mentions and figures two ‘‘small seed-like centers opposite the 
middle of the premaxillaries’’ as maxillaries, but he makes no 
record of muscles connected with them. The writer finds in the 
position described by Parker a minute ossification on each side 
(fig. 3, max.). This may, however, be larger on one side than on 
the other; in fact is wanting on one side in some specimens. Its 
minute size, and possibly complete absence on both sides in some 
instances, may explain the failure of some investigators to find it. 
It has no muscles connected with it. It may possibly represent 
a maxilla as Cuvier, Vaillant and Parker believed. 
Huxley (’78) states, and his account is approved by Parker, 
that from the tip of the postorbital cartilage in Siren ‘‘a band of 
