324 ASiiiu.t:. 



Subclass III. GANOIDEI. 



Fishes with the skeleton more or less ossified. 

 Bulb of the aorta muscular, with numerous valves. 

 Branchiae free ; gill-cavity protected by a gill-cover. 

 Intestine with a spiral valve. Optic nerves not de- 

 cussating. Ventral fins abdominal, if present. 



Cfr. Miiller, Abhandl. Ak. Wiss. Berlin, 1844, p. 141. 



SynojJsis of the Families. 



I. HOLOSTEI. Body covered with scales ; skeleton bony. 



A. Scales cycloid 1. Amiid^, p. 324. 



B. Scales ganoi<^. 



a. Fins without fulcra 2. Polypteridae, p. 326, 



h. Fins mth fulcra 3. Lepidosteidae, p. 328. 



II. CHONDROSTEI. Skin naked, or with osseous bucklers. 



Skeleton partly cartilaginous. 



A. Mouth small, transverse, inferior. 1. Acipenseridae, p. 332. 



B. Mouth lateral, very wide 2. Polyodontidae, p. 346. 



Order I. HOLOSTEI. 



Skeleton bony; body covered with scales. 



Holostei, Miiller, Abhandl. Ak. Wiss. Berlin, 1844, p. 147. 

 Lepidoganoidei (part.), Owen, Cotnjyar. Anat. of Vertebr. i. p. 12. 



Freshwater fishes of North America and Africa. 



Fam. I. AMIlDiE. 



Scales cycloid ; a long soft dorsal fin. Abdominal 

 and caudal parts of the vertebral column subequal in 

 extent. Pseudobranchiae none. 



Fresh waters of North America. 

 One genus only. 



