Osteology of Kaupichthys diodontus — GOSLINE 
Fig. 3. a, Cranium from the side; b, from above; 
c, from below (teeth omitted); d, from behind; 
e, sagitta. al, Alisphenoid; bo, basioccipital; eo, 
exoccipital; ep, epiotic; ev, premaxiilary-ethmo- 
vomer; fm, foramen magnum; fr, frontal; if, inter- 
orbital foramen; ob, otic bulla; or, orbitosphenoid; 
pa, parietal; pr, prootic; ps, parasphenoid; pt, pte- 
rotic; so, supraoccipital; sp, sphenotic. 
(see Fig. 3 £ this paper and Frost, 1926: 99). 
On the dorsal surface of the skull the frontals 
are completely divided by suture; the pari- 
etals (pa) are rather large for eels; the pte- 
rotics are elongate. On the posterior face of 
the skull the foramen magnum (fm) is large 
311 
and the socket for the articulation of the 
vertebral column relatively small for eels. 
The first vertebra is not fused to the skull. 
The branchial apparatus (Figs. 4 and 5) 
is of normal eel type, without specialized 
features. There are 15 branchiostegal rays 
(br) on each side; those of the two sides of 
the head do not overlap on the midventral 
line and rather closely encircle the opercular 
bones behind. The upper pharyngeals (up) 
articulate with the upper ends of the third 
and fourth branchial arches. The fourth arch 
closely adjoins the lower pharyngeals (Ip) 
below. Both upper and lower pharyngeals 
Fig. 4. Right side of hyoid arch, from below, 
bh, Basihyal; br, branchiostegal ray; ch, ceratohyal; 
gl, glossohyal; uh, urohyal. 
Fig. 5. Median view of right gill arches, some- 
what opened out. bb, Basibranchial; cb, cerato- 
branchial; eb, epibranchial; gc, gill cleft; lp, lower 
pharyngeal; up, upper pharyngeal. 
