TELEOSTS. 257 



fins present. Angnilla vulgaris, the common eel of Europe and America. 

 Conger vulgaris, conger eel, almost cosmopolitan. The name Leptoceph- 

 alus was given to the young of both Anguilla and Conger. MuRiENiD^, 

 gill slits small and rounded, pectorals lacking. Murcena, the murrys of 

 warmer seas. The Apodes are an old group, Anguilla dating from the 

 cretaceous. They have possibly descended from the Isospondyli. 



Sub-Order 3. Lyomeri. 



Deep sea physostomes with eel-shaped bodies, large heads, 5-6 simple 

 gill arches; skull imperfectly ossified. In some features they appear de- 

 generate, in some primitive. But few specimens known. Eiirypharynx, 

 Castrostoinus. 



Sub-Order 4. Haplomi. 



Physostomes with the head usually scaly, scales cycloid ; shoulder 

 girdle attached to the cranium ; teeth present; no adipose dorsal. Umbrid,e 

 (mud-minnows), teeth villiform; maxillaries forming the lateral part of the 

 jaw. Umbra. Esocid^e, pikes, maxilla similar to the last ; teeth are card- 

 like and unequal. Esox, pickerel, pike, muskalunge. Esox dates from the 

 miocene, Ischyrhiza from the cretaceous of the United States. Cyprino- 

 DON'TlD.E, premaxilla forms the entire upper jaw ; vent normal. Eunduhis, 

 the mummichogs or killifishes, Anableps. Cyprinodon. Lebias from the 

 miocene. Amblyopsid^ (Heteropygii) ; jaws as in cyprinodonts ; vent in 

 the branchial region ; species mostly cave inhabitants (American) and 

 have greatly degenerate eyes. Amblyopsis, Chologaster, The Stra- 

 TIODON'TID/E are extinct. Cimolichthys, upper cretaceous. 



ORDER III. SYNENTOGNATHI. 

 Large physoclistous bladder ; fins without spines ; lower 

 pharyngeals united into a single bone ; shoulder girdle con- 

 nected to cranium ; a row of keeled scales on the belly ; marine. 

 These forms are allied to the percesoces and the spine-finned 

 fishes. 



ExoccETlD^E or SCOMBRESOCID.E, gill openings wide ; jaws more or 

 less prolonged ; maxillary and premaxillary free ; and the third upper pha- 

 ryngeal greatly enlarged. Scomberesox, bill-fish, Exoccetus, flying-fish. 

 Isteus, etc., cretaceous. Belonid^, jaws greatly elongate, the lower the 

 longer ; maxillaries and premaxillaries closely united, third upper pha- 

 ryngeal not enlarged. Tylosurus, needle-fish ; Belone, bony gars, appears 

 in the miocene. 



ORDER IV. HEMIBRANCHII. 



Teleosts with the pharyngeals reduced in number, the lower 

 not united ; gills pectinate ; mouth bounded by premaxilla above ; 

 scapular arch connected to cranium ; ventrals sub-abdominal. 



