688 The American Naturalist. [August, 
retractor muscle functioning as a retractor bulbi — the anterior por-` 
tion has undergone degeneration. 
Kingsley further states that the described apparatus is not in the 
proper location to be compared to the tentacular organ of the Gymno- 
phiona. In elucidating this point it is of service to compare figure I 
with figure IV taken from Die Anatomie der Gymnophionen von 
Wiedersheim. 
Figure IV. Cross section of Siphonops annulatus. NPr, naso premaxillary ; 
Vo. vomer; M, maxillary ; Atts, outer tentacle sheath ; ITts, inner tentacle sheath 
After Weidersheim. 
It is seen that the columar-lined canal, inner tentacle sheath and 
outer tentacle sheath in Siphonops, have the same relation as in Am- 
phiuma. It is further seen that the inner sheath of Siphonops is in- 
voluted ventrally to surround the tentacle while in Amphiuma a similar 
involution is seen on the dorsal side in Fig. III. In both genera the 
organ is covered merely. by the skin and its subjacent tissue. The 
glandular tissue is not shown in Fig. IV as the section is anterior to the 
orbital gland. It is true the maxillary bone overhangs the apparatus 
in Sipbonops whereas such is not the case in Amphiuma. In beha 
this contrast I quote from Cope (Bulletin of the United States National 
Museum, No. 34, p. 214): “There is also a very large foramen or 
canal passing through the o. maxillare from near its middle to the 
orbit, foreshadowing the canalis tentaculiferus of the cecilia.” Fig. I. 
is a section posterior to where the canal would enter the maxillary bone. 
Among the Gymnophiona there is considerable variation as to the rela- 
tion of the apparatus to the maxillary bone as the following from Wie- 
dersheim, p. 47 shows: “Sprengt man nun zum Behuf klarerer Ein- 
sicht die Deckknochen auf der betreffenden Schidelhafte volkommen 
ab, so wird man ein weissliches, walzenformiges Organ gewahr, wel- 
