378 Mr. C. T, Regan on the Osteology and 



pelvics usually absent. Pigeraaxillaries not developed as 

 distinct elements ; maxillaries bordering the mouth, sepa- 

 rated anteriorly by the ethmoid*; hyo-pahitine bones 

 reduced to 2 or 3, hyomandibular, quadrate, and palato- 

 pterygoid, the last sometimes absent ; lower jaw of dentary 

 and articulare ; opercular bones small, the membrane covering 

 the large branchial chambers chiefly supported by the long 

 branchiostegals. A single pair of dentigerous upper pha- 

 ryngeals, opposed to the separate lower pharyngeals. Skull 

 long and low ; prsemaxillaries, mesethmoid, and lateral 

 ethmoids represented by a single dentigerous f bone ; parietals 

 meeting in front of the supraoccipital ; no exoccipital con- 

 dyles \ ; no opisthotic, but other otic bones well developed ; 

 pterotic extending forward above sphenotic to alisphenoid ; 

 paired §orbitospheiioids; nobasisphenoid. No post-temporal ; 

 supra-cleithrum attached by ligament to the vertebral column ; 

 hypercoracoid and hypocoracoid small, laminar ; no meso- 

 coracoid. Vertebrse numerous ; arches ankylosed to centra; 

 prrecaudals with strong parapophyses bearing the ribs; epi- 

 neurals and epipleurals usually present. Gonoducts reduced 

 to genital pores. 



Tlie peculiarities of the skull, jaws, suspensorium, and 

 pectoral arch separate the Apodes very sharply from the 

 Isospondyli, of which they must be regarded as an offshoot. 

 They correspond to the family Mura^nidaj of Giinther after 

 removal of the Saccopharyngidge, now generally regarded as 

 comprising a separate order, Lyomeri (see ' Annals,' Sept. 

 1912, p. 347). 



Except for tlie elevation of the subfamilies to family rank 

 and liie addition of the more recently discovered Urenchelid^e, 



* Accordiug to Boulenger (Camb. Nat. Hist. p. 600) the maxillaries 

 of the Muraeniclse are palato-pterygoids. I tind that in all their relations 

 these bones are the same in the MurfenidaB as in the other families ; 

 distally they are external to the mandibles ; moreover tlie true palato- 

 pterygoids are present in the usual place, but reduced to mere threads of 

 bone. 



t In Heterenchelys and also in Synaphobranchus the vomerine teeth are 

 separated by an interspace from the praemaxillary teeth and the vomer is 

 a distinct bone. It can hardly be doubted that the dentigerous bone in 

 front of the vomer and between the maxillaries represents the priie- 

 maxillaiies ankylosed to the mesethmoid. 



X As in the Isospondyli an anterior half-centrum is very tirmly united 

 to the basi- and exoccipitals. 



§ The orbitosphenoids lie in front of the alisphenoids and usually 

 separate the parasphenoid fiom the frontals ; rarely {MoriiKjua and some- 

 times in AnyuilJn) the parasphenoid and frontals meet, concealing the 

 orbitosphenoids. 



