XIII 



PHYLUM C HOE DATA 



219 



This order includes the Sturgeons {Acipenser, Fig. 873, and 

 ScaphirJiJjncMis) found in the rivers of Europe, Asia, and Nortli 



/^■■o 



Fig. 873.— Acipenser rutbenus (Sturgeon). 6. barbels ; c 7. caudal fln ; <?.^. dorsal fin ; 

 2)c(. f. pectoral fin ; pv. f. pelvic fin ; sc. scutes ; v. f. ventral fin. (After Cuvlcr.) 



America ; the curious spoon-billed Polyodon, from the Mississippi ; 

 and PsephuriLS from the rivers of China. 



Order 3. — Holostei, 



Teleostomi iu which the paired fins have no basal lobe. The 

 chondrocrauium is well ossified by replacing bones and investing 

 bones : branchiostegal rays are present. The vertebral column 



IL 



p^r 



Fio. 874.— IiepidOSteus platystomus (Bony Pike), e. f. caudal fin; d.f. dorsal fin; 

 C fulcra; LA. lateral 4i)ic ; /-'<. /. pectoral fin ; 'j)v. f. pelvic fin; v.f. ventral fin. (After 

 Cuvier.) 



consists of bony vertebrae, and the tail is heterocercal or nearly 

 homocercal. The pelvic fins are abdominal. A reduced spiral 

 valve, a conus arteriosus, and an optic chiasma are present. 



This order includes the Gar-pike or Bony Pike {Leijidosteus, 

 Fig. 874), from the fresh waters of North and Central America and 



B 



br.m, 



Fig. 876. — Amia calva (Uow-fin). A, the entire animal ; B, ventral vievsr of throat, br. m. 

 branchiostegal ui(.njlrane ; c. /. caudal fin; d.f. dorsal fin; jvy. jril. jugular plate; j"-'*-/- 

 pectoral fin ; pv. f. pelvic fin ; v. f, ventral fin. (After Giinthcr.) 



