166 PISCES. 



Fam. Spatularidae (Lb'ffelstore). Spatularia [Poly odori\ folium Lac., Missis- 

 sippi ; Sp, gladius Martens, Yantsekiang. 



Tribe 2. Crossopterygii. Ganoids with two broad jugular plates 

 instead of the branchiostegal rays, and usually with a pointed 

 (diphycercal) caudal fin. The shafts of the pectoral as well as of the 

 pelvic fins, which are placed far back, are invested with scales, which 

 also cover the rays. The scales are sometimes thin and cycloid, 

 sometimes strong and rhomboid. The Crossopterygii lead to the 

 Dipnoi and Amphibia. 



Fam. Polypteridae. With rhomboid scales, and dorsal fins divided up into 

 a number of small fins. Polypterus lickir Geoffr. (fig. 607), with from eight 

 to sixteen small fins, rivers of Tropical Africa ; CalamoichtJiys calabaricus 

 Smith, Old Calabar. 



Tribe 3. Euganoides (Bony Ganoids). Ganoids with rhomboidal 

 scales, and usually with fulcra on the anterior border of the fins. 

 They have numerous branchiostegal rays. The pelvic fins are placed 

 between the pectoral and anal fins. 



Fam. Lepidosteidae (Gar- Pikes. Bony Pikes). Form of body elongated, 

 pike-like. The dorsal fins are placed far back ; the caudal fin heterocercal 

 and sharply cut off. Fresh waters of Cuba, Central and North America. 

 Lepidostcus platystomus Eaf. ; L. osseus L. ; L. spatula Lac. 



Tribe 4. Amiades. Bony Ganoids, with large round enamelled 

 scales, bony branchiostegal rays, and heterocercal caudal fin. There 

 are no fulcra. 



Fam. Amiadae. Amia calva Bonap., rivers of Carolina ; most nearly 

 allied to the bony fishes (Clupeidce and Salmonid-ai). 



Order 5. TELEOSTEI (BONY FISHES). 



Fishes with bony skeleton, with free gills (usually four on each side) 

 and an external branchial operculum< There is a bulbus arteriosus 

 with two valves at its base. The optic nerves do not form a chiasma. 



The Teleosteans comprise by far the greatest number of all fishes, 

 and are distinguished from the cartilaginous fishes and Ganoids by a 

 number of anatomical characters. They possess a simple bulbus 

 arteriosus with only two valves, which are placed opposite to each 

 other at the origin of the bulbus. The bulbus arteriosus is not a 

 separate part of the heart with independent pulsation, but the 

 thickened commencement of the cardiac aorta. Spiracles and a 

 spiral valve of the intestine are never found. The optic nerves 

 simply cross one another, or the fibres of the one pass between the 



