386 Osteology and Classification of the Order Apodes, 



in jaws and on vomer. Nostrils lateral ; gill-openings sepa- 

 rate ; pharyngeal apertures of branchial clefts wide ; pha- 

 ryngeals ovate or oblongs covered with small teeth. Frontals 

 ankylosed to form a single bone ; vomer ankylosed to ethmoid ; 

 orbitosphenoids small, Suspensorium vertical or directed 

 obliquely forward ; palato-pterygoid an elongate lamina. 

 4 pectoral radials. Neural spines well developed ; caudal 

 and posterior prgecaudal vertebrse with lateral transverse 

 processes, in addition to haemal arches or parapophyses ; ribs 

 and intermuscular bones feeble. 



This large and varied family corresponds to tb.e Lepto- 

 cephalidas, Mursenesocidse (except Murcenesox)^ and Nettasto- 

 midge of Jordan and Evermann. 



Principal genera : Heteroconger, Promi/llanfor, Congro- 

 muroena^ Conger, Congrosoma, Ui'oconger, Coloconger, Neo- 

 conger, Stilbiscus, Leptoconger, Gordiichthys, Iloplunnis, 

 Oxyconger, Xenomystax, Nettastoma, Saurenchelys, Eetten- 

 chelys, Chlopsis, Venejica, Metopomycter. 



In this family there is a more or less prominent vertical 

 ridge on the middle of each centrum and the parapopliysis is 

 more or less completely divided into two. Echelion montium 

 (Hay, Bull. Amer. Mus. xix. 1903, p. 441, pi. xxxvii. 

 ligs. 2-6), from Mount Lebanon, described as an apparently 

 diplospondylous eel, had vertebrge of this type. 



Derichthys serpentinus, Gill, is said to have distinct pra3- 

 maxillaries, but this requires confirmation, as in other cha- 

 racters it seems to be a member of the family Congridse. 



Family 13. Echelidse. 



Differs from the Congridse in the labial nostrils, the rather 

 strong ribs and intermuscular bones, and the vestigial neural 

 spines. 



Echelus, Ahlia, Myrophis, Paramyrus, Ghilorhinus, Murcen- 

 ichthys. Eomyrus, from the Upper Eocene of Belgium, also 

 belongs to this family (Storms, Bull. Soc. Beige G^ol. x. 

 1896; pp. 225-240, pis. v., vi.). 



Family 14. Ophichthyidae. 



Differs from the Congridse in the absence of the caudal fin, 

 the tip of the tail projecting beyond the dorsal and anal, the 

 labial nostrils, and the vestigial neural spines. 



Sphagehranchus, Pisodontophis, Callechelys, OpJncJithijs, 

 BrachysomopMs, &c. 



