35] THE NASAL ORGAN IN AMPHIBIA—HIGGINS 35 
THE NASAL CAPSULE OF THE GYMNOPHIONA 
EPICRIUM GLUTINOSUM 
Considerable diversity of opinion has existed-in the past in regard to 
the systematic position of the Caecilians. Cope (1889) classed them as a 
family of the Urodeles, related to them through Amphiuma; while the 
cousins Sarasin (1890), following Cope, also regarded them as Urodeles, 
considering Amphiuma a neotenic Caecilian. Kingsley (1902) reviewed 
the evidence as to the position of the group, showing that many points 
supposed to indicate relationships, were based upon erroneous statements 
or misconceptions and that the Gymnophiona are to be regarded as a 
distinct group, without any close relations to any other existing Amphibia. 
To determine to what extent, if any, the nasal capsules of this group 
would shed light upon their relationships to the Urodeles, two larvae of 
Epicrium glutinosum were studied,in which chondrification was well 
advanced and the nasal capsules completely formed. 
Peter (1898) has described the chondrocranium of a young Caecilian; 
and Winslow (1898) a stage in which the embryo is still spirally coiled 
within the egg, considerably younger than my earlier material. In con- 
trast to all other Amphibia, the trabeculae of each side are double (Fig. 
32), consisting of a dorsal and ventral bar in the position of trabecular 
crest and trabecula, the dorsal doubtless being the homologue of what 
Sewertzoff (1897) has called the alisphenoid cartilage of the Elasmobranchs. 
On either side of the eye, the dorsal and ventral trabeculae are united by a 
postorbital and preorbital band, the optic nerve passing through the 
large gap between them. Anterior to the preorbital band, the lower or 
true trabecula inclines toward the median line, and is united with its mate 
by a slightly convex planum basale (pd), which lacks the trabecular 
thickenings of the plana of Urodeles. The posterior and lateral margins 
of the planum are straight, the latter more anteriorly curving outward 
where it passes into the posterior margin of the cornu trabeculae, which 
forms the floor of the capsule; while anterior to the cornu the planum 
narrows considerably and is continuous in front into a pair of small proc- 
esses, the tips of the trabeculae, separated from each other by a wide 
internasal space. 
The planum verticale (fv) is a narrow plate of cartilage, arising from 
the ‘anterior half of the median line of the basale and extending dorsally 
