34 



The Ganoids 



and essentially to the Cycloganoidei of Gill. The Protospondyli 

 (nporos, before; <T7rov$v\os, vertebra) of Woodward contains 

 essentially the same elements. 



Pachycormidae. In the family of Pachycormida the noto- 

 chord is persistent, the ethmoids and vomer fused and pro- 

 jecting between the maxillaries to form the prominent snout, 

 the teeth large, the body fusiform, the dorsal short, with slender 

 rays and few fulcra or none, and the scales are thin and rhombic. 

 The numerous species are characteristic of the Triassic, Jurassic, 

 and Cretaceous. In Sauropsis (longimana) the body is elon- 

 gate, and the pectoral fins are large and sickle-shaped. Euthy- 

 notus has small fulcra. In Pachycormus (macropterus, esocinus, 

 etc.) the form is robust and the ventral fins are wanting. In 

 Hypsycormus ventrals are present, and the caudal deeply forked. 



In the American family of Protosphyraznida the jaws are 

 armed with very strong teeth, as in the Barracuda, which, 

 however, the species do not resemble in other respects. Proto- 

 sphyrana nitida, pemiciosa, and numerous other extinct 

 forms, some of them of large size, were voracious inhabitants 

 of the Cretaceous seas, and are found fossil, especially in North 

 Carolina and Kansas. Numerous species called Erisichthe and 

 Pelecopterus are all referred by Hay to Protosphyr&na. In 

 this family the scapula and coracoids are ossified, and perhaps 

 the vertebras also, and, as Dr. Hay has recently suggested, the 

 Protosphyranida may really belong to the Isospondyli. In any 

 event, they stand on the border-line between the most fish-like 

 of the Ganoids and the most archaic of the bony fishes. 



The Liodesmufo (genus Liodesmus) are much like Amia, but 

 the notochord is persistent, its sheath without ossification. 

 Liodesmus gracilis and L. spratttformis occur in the lithographic 

 stones of Bavaria. Woodward places Liodesmus with Megalurus 

 among the Amiida. 



The Bowfins: Amiidae. The Amiidaz have the vertebrae more 

 complete. The dorsal fin is many-rayed and is without distinct 

 fulcra. The diamond-shaped enameled scales disappear, giving 

 place to cycloid scales, which gradually become thin and mem- 

 branous in structure. A median gular plate is developed be- 

 tween the branchiostegals. The tail is moderately heterocercal, 

 and the head covered with a bony coat of mail. 



