EMERSON: ANATOMY OF TYPHLOMOLGE. 
47 
angle made by their divergent posterior processes. The position of 
the supra-occipital here is identical with its position in the larva of 
Spelerpes ruber and very similar to its position in Triton alpestris 
as shown by Wiedersheim (’77, pi. 6, fig. 83). In Necturus this 
supra-occipital arch is confluent with the cartilaginous otic capsules. 
The basi-occipital arch is also present. Anteriorly it appears as 
a flat bit of cartilage on the dorsal surface of the posterior end of 
the parabasal, connecting the ventral surface of the periotics. It 
becomes broader, and posterior to the parabasal narrows again, its 
dorsal surface having a median longitudinal depression. Here the 
median process of the first vertebra lies dorsal to it and is contigu¬ 
ous to it laterally. 
The basi-occipital in Typhlomolge is identical in shape and posi¬ 
tion with that of the Spelerpes larva and corresponds closely with 
that of Triton alpestris (Wiedersheim, ’77, pi. 6, fig. 83). The 
arrangement of both basi- and supra-occipital arches in the Pro- 
teidae is quite different. 
Another characteristic of the chondrocranium common to Typhlo¬ 
molge and Spelerpes larva is the entire lack of bony or cartilagi¬ 
nous nasal capsules. In the Proteidae the capsules are large and 
cartilaginous. 
Osseous Elements. 
The otic and occipital region. — In the otic and occipital region 
the skull of Typhlomolge differs markedly from that of the Pro¬ 
teidae and resembles that of the larva of Spelerpes closely. While 
in Necturus and Proteus the osseous elements, exoccipitals, peri¬ 
otics, and opisthotics are quite distinct and separate, embedded in 
the cartilage of the parachordal region of the chondrocranium, in 
Typhlomolge, as in Spelerpes, these elements are not differentiated 
but are fused with the parachordal region of the chondrocranium 
into two oval bony masses, the periotics or otic capsules, on which 
the configuration of the semicircular canals is very plain. Stejneger 
makes out “the presence of what appears to be an intercalary bone.” 
If, as seems probable, lie follows Cope’s nomenclature and uses “in¬ 
tercalary” for “ opisthotic,” he is mistaken, for the opisthotic as 
such does not exist in this form. 
The anterior portion of the periotic, corresponding to the pro-otic 
