78 



FISH GALLERY. 



ring-shaped or biconcave. The teeth are sharp; the lower jaw 

 has a movable premandibular bone ; the branchiostegal rays are 

 numerous. These fishes range from the Lower Oolite to the 

 Upper Chalk; there are two genera, Aspidorhynchus (213) and 

 Belonostomus. 



Fig. 44. — Restoration of Aspidorhynchus acutirostris. 

 (After A. S.Woodward.) 



In the family Lepidosteidae the fin-fulcra are large ; the tail has 

 a fairly symmetrical outline although the vertebral axis is con- 

 spicuously uptilted ; the centra of the vertebrae are well ossified 

 and are convex in front and concave behind (opisthoccelous) ; the 

 teeth are numerous, of unequal size, and the larger ones have the 

 bases folded in a manner reminiscent of those of the Holopty- 

 chioides. The maxilla consists of several small bones in series ; 

 the branchiostegal rays are usually three. The conus arteriosus 

 has eight longitudinal rows of valves, five in each row. Remains 

 of species of Lepidosteus are known from Eocene and later strata. 



The existing species of Lepidosteus, known as Gar -pikes (214- 

 216, and fig. 45), inhabit the fresh waters of North America 



Fig. 45. — Broad-nosed Gar-Pike, Lepidosteus viridis. 



and Cuba and one species occurs in China. The fishes are 

 sluggish but voracious. They themselves are valueless as food, 

 and they create havoc among other fresh-water fishes, against 

 whose attacks they are invulnerable. Except in the breeding 

 season the Gar-pike frequents the deeper parts of the rivers and 

 lakes. The fish rises constantlv to the surface, where it emits 



