ESOCIFORMES 403 



SUB-FAMILY 1. BELONINAE, with zygapophyses, and the maxilla fused 

 to the premaxilla ; Belone, Guv., Gar-Fish. SOB-FAMILY 2. EXOCOETINAE, 

 with separate maxilla, no zygapophyses, and enlarged third upper 

 pharyngeals ; Scombresox, Lac. ; Hemirhamphus, Cuv. (Fig. 397) tropical 

 and temperate seas ; and Eocene, Europe. Arrhamphus, Gthr. ; Pacific. 

 Exocoetus, Art. (Fig. 396) ; tropical seas. 



INCERTAE SEDIS. 



Family AMMODYTIDAE. A small family of elongated marine fish, 

 whose systematic position is very uncertain ; they are placed near the 

 Scombresocidae by Boulenger, in the Ophidiidae by many authors. 



In the extinct Cobitopsis the pelvic fins are present and abdominal, 

 in the modern forms they are lost. The parietals are separated, the 



FIG. 398. 

 americanus, De Kay. (From Jordan and Evermanu.) 



maxillae excluded from the margin of the mouth, which is protractile, 

 the scales small and cycloid, the teeth small or absent, the air-bladder 

 absent, and there are no parapophyses. 



Ammodytes, L. (Fig. 398), Sand Eel ; Northern hemisphere. 

 Hypoptyehus, Steind. ; Japan. Cobitopsis, Lorn. ; Oligocene, France. 



Series 2. 

 Sub-Order 2. ANGUILLIFORMES (Apodes). 



The Eels are a highly specialised group. They acquire a very 

 elongated shape ; the median fins are extremely long and usually 

 confluent behind ; the tail is truncated, both hypural bones and 

 caudal fin being lost, and ends in a symmetrical gephyrocercal tip 

 {Fig. 400). The paired fins also tend to disappear, traces of the 

 pelvics being found only in the extinct Urenchelys, which is also 

 remarkable for the possession of a caudal fin (A. S. Woodward 

 [504-5], Hay [205]). As a rule, the number of vertebrae is greatly 

 increased, and the notochord persists more than usual among 

 modern Teleosts. The parietals meet above. It is in the visceral 

 skeleton that the modifications are most conspicuous. Normal 

 premaxillae are never found ; either they have been lost or they 

 have fused with the ethmoid and vomer (Fig. 402) ; these two bones 

 coalesce. The maxillae themselves may be absent (Muraenidae) ; 

 .and even the ptery go -quadrate arch may become discontinuous 



