XXII HAPLOMI 605 
ethmo-vomer ; palato-pterygoid bone separated from hyomandi- 
bular arch; branchial openings into the pharynx narrow slits; 
no tongue, 
The body is naked, pectoral fins are usually absent, and the 
gill-cleft is a small round opening. The opercular bones are 
much reduced in size, and the pectoral arch may be totally absent. 
Voracious marine Fishes, inhabiting tropical and sub-tropical 
waters, being especially abundant about coral reefs. Some 120 
species are known, many reaching a very large size, and being 
also remarkable for their variegated coloration. The genera are 
mostly founded on the dentition, which shows much diversity ; 
the following are the principal: — Myroconger, Enchelycore, 
Muraena, Thyrsoidea, Lycodontis, Pythonichthys, Echidna, Chan- 
nomuraend. The Muraena of the ancient Romans, J/uraena 
helena, of the Mediterranean, Eastern Atlantic, and neighbouring 
parts of the Indian Ocean, occurring exceptionally .as far north 
as the English coast, grows to 4 feet, and its flesh was more 
esteemed than that of any other Fish, large numbers being reared 
in specially constructed reservoirs near the sea, and fed on the 
corpses of slaves. Channomuraena vittata, from the coast of Cuba, 
is known to attain a leneth of 8 feet, and Vhyrsoidea macrura, 
from the Indian Ocean and the Malay Archipelago, to upwards 
of 10 feet. 
Sub-Order 5. Haplomi. 
Air-bladder, if present, communicating with the digestive 
tract by a duct. Opercle well developed. Pectoral arch sus- 
pended from the skull; no mesocoracoid arch. Fins usually 
without, rarely with a few spines; ventrals abdominal, if present. 
Anterior vertebrae distinct, without Weberian ossicles. 
The absence of the mesocoracoid arch distinguishes the 
Haplomi from the Malacopterygii, with which they are united 
by various authors. They lead to the Percesoces through the 
Cyprinodontids, and to the Lower Acanthopterygians, such as 
the Berycidae, through the Scopelids, Stephanoberycids, and 
Percopsids, as is evidenced by the structure of the mouth and 
the forward position, in some of the genera, of the ventral fins, 
which, however, are never attached to the pectoral girdle. Most 
of the forms which are here included inhabit either fresh water 
or the deep sea. 
