26 



The Ganoids 



and German Triassic, and Lepidotes minor in the English Triassic. 

 Another well-known European species is Lepidotes mantelli. 



The Isopholidce (Eugnathida) differ from the families last 

 named in the large pike-like mouth with strong teeth. The 

 mandibular suspensorium is inclined backwards. The body is 

 elongate, the vertebrae forming incomplete rings; the dorsal 

 fin is short with large fulcra. 



Isopholis dentosus is found with numerous other species in 

 the British Triassic. Caturus furcatus is especially characteristic 



FIG. 16. Tetragonolepis semicinctus Brown. Lias. Family Semionotidce. 

 (After Woodward.) 



of Triassic rocks in Germany. Ptycholepis marshi occurs in 

 the Connecticut valley. 



The Macrosemiida are elongate fishes with long dorsal fin, 

 the numerous species being found in the Triassic, Jurassic, and 

 Cretaceous of Europe. Macrosemius rostratus has a very high, 

 continuous dorsal. Macropistius arenatus is found in the 

 Cretaceous of Texas, the only American species known. Promi- 

 nent European genera are Notagogus, Ophiopsis, and Petalopteryx. 



Intermediate between the allies of the gars and the modern 

 herrings is the large extinct family of Pholidophoridcs, referred 

 by Woodward to the Isospondyli, and by Eastman to the Lepi- 

 dostei. These are small fishes, fusiform in shape, chiefly of 



