Osteology of Gorgasia punctata — Rosenblatt 
opal” caudal rays. A strong process curves 
forward and downward from the neural arch 
element. It probably serves as a muscle attach- 
ment and may be associated with tail-first dig- 
ging in sand. An essentially similar caudal 
skeleton has been figured by Bohlke for Nystac- 
tichthys halts, and I have found the caudal 
skeleton of 7 aenio conger digueti, T. herrei, T. 
hassi, and T. n.sp. to be basically the same. 
CIRCUMORBITALS AND LATERAL LINE CA- 
NALS: The circumorbital ring is complete, con- 
sisting of at least five weakly-ossified and roof- 
less bones. Apparently the small "supraorbital” 
illustrated by Asano (1962) for several Japa- 
nese congrids is absent. The temporal canal is 
encased in bone in G. punctata only, among 
the species examined. The lateral-line canal 
along the body is contained in a series of ossi- 
cles (lateral-line scales?). Anteriorly these are 
developed as unconnected but closely opposed 
tubes, which posteriorly gradually become less 
strongly ossified, so that along the midbody 
there is an open trough consisting of a series 
of ossified half-rings. In the species of Taenio- 
conger examined, the lateral-line ossicles are 
developed as short, widely-spaced, troughlike 
ossifications. 
RELATIONSHIPS OF THE HETEROCONGRINAE 
The heterocongrines resemble the Ophichthi- 
dae in several respects. In both groups the ribs 
are laminar, and the neural spines reduced 
(vestigial in the ophichthids) , as are the cir- 
cumorbitals. In Gorgasia and in some species 
of Taenio conger the caudal fin is short and the 
tail-tip fleshy. In all, the body is elongate and 
circular in cross section. The pectoral fin, as in 
many ophichthids, is reduced (varying from 
small in Gorgasia to minute in Nystactichthys 
and Taenioconger to absent in Heteroconger) . 
In addition to these structural characters, both 
groups share the sand-dwelling habit. However, 
the characters given by Gosline (1951) to 
separate the Congridae and the Ophichthidae 
(except that it is now known that many con- 
grids have an auditory bulla) serve to distin- 
guish Gorgasia and its allies from the ophich- 
thids as well. In addition, it may be noted that 
the Congridae have the parapophyses divided 
by a vertical ridge and have a vomerine process, 
95 
to which the palatopterygoid is ligamentously 
attached — features that appear to be lacking in 
the Ophichthidae. 
The superficial similarities between Gorgasia 
and the ophichthids are certainly parallel adap- 
tations to a similar mode of life, and the minor 
osteological similarities may be adaptations as 
well. 
Although recognizing the close relationship 
between the two groups, Klausewitz and Eibl- 
Eibesfeldt (1959) maintained the family Het- 
erocongridae as distinct from the Congridae. 
Their action was based on behavioral differ- 
ences and on bone reduction and "Fensterbil- 
dung” (fenestration?) in the skeleton. How- 
ever, their illustration of the head skeleton of 
Xarifania h. hassi shows a well-developed skull 
and well-integrated jaws, suspensorium, and 
opercular series. On the basis of the present 
investigation there are no grounds (except that 
the circumorbital series is less well developed) 
for the contention that the skeleton has under- 
gone important reduction in comparison with 
that of the Congridae. 
There is, in fact, nothing in the osteology of 
the heterocongrines I have examined that would 
preclude the inclusion of the group in the Con- 
gridae. The heterocongrines possess the basic 
congrid characters of ankylosed frontals, for- 
ward-inclined suspensorium, few and nonover- 
lapping branchiostegals, maxillary-ethmoid ar- 
ticulation near tip of snout, caudal vertebrae 
with transverse processes, skull truncate poste- 
riorly, parapophyses divided by a vertical ridge, 
and a lateral process on the vomer. 
The chief osteological differences are: neural 
spines absent on most abdominal vertebrae (and 
on most caudal vertebrae as well in Gorgasia ) ; 
neural and haemal arches becoming high and 
bladelike near the tail-tip ; urostylar vertebra 
better developed, and supporting structure of 
caudal more complex; epineurals and epipleu- 
rals lost 10-15 vertebrae before tail-tip; cir- 
cumorbital series reduced and less ossified. 
Stronger divergences from the basic congrid 
type are found in nonosteological characters. 
In most of the Congridae the muzzle is elon- 
gate, and the olfactory organ is well developed, 
with numerous lamellae. In the heterocongrines 
the muzzle is short, the eye is relatively large, 
and the olfactory rosette is much smaller, with 
