12 ANATOMY OF VEETEBEATES. 



Order VII. LOPHOBRANCHII. 



Endoskeleton partially ossified, witliout ribs ; exoskeleton ganoid ; 

 gills tufted ; opercular aperture small ; swim-bladder without air- 

 duct. Males marsupial. 



Fam. 1. Hippocampidee. Ex. Sea-horse. 

 2. Symjnatldda. Ex. Pipe-fish. 



B. Arterial bulb mviscular, M'ith more than one row of valves. 

 Optic nerves not decussating. 



Order VIII. GANOIDEI. 



Endoskeleton cartilaginous, partly bony, or ossified ; in a few 

 recent and in most palteozoic extinct forms, notochordal ; exo- 

 skeleton as ganoid scales or plates ; fins usually with the first 

 ray a strong spine ; caudal fin in most unsymmetrical ; a swim- 

 bladder, often cellular, and with an ah-duct ; intestine in many 

 with a spiral valve. 



Suborder I. Lepidoganoidei. 



Fam. 1. Salamandroidei. Ex. Lepidosteus, Polypterus. 



2. Pijciwdontidce. Ex. Pj'cnodus. 



3. Lepidoidei. Ex. Dapedius. 



4. Leptolepldm. Ex. LejJtolejois. 



5. Acanthodei. Ex. Acanthodes. 



6. Dipteridw. Ex. Dipterus. 



7. Ccelacaiitld. Ex. Coelacauthus. 



8. HoloptijchidcE. Ex. Holoptychius. 



Suborder II. Placogaxoidei. 



Fam. 1. Sturionidce. Ex. Sturgeon. 



2. Ostracostei. Ex. Pterichthys. 



Subclass III. Order IX. HOLOCEPHALI. 



Endoskeleton cartilaginous, subnotochordal ; cranial wall com- 

 plete ; tympanic pedicle confluent thcrewitli ; endoskeleton as 

 placoid granules. Anterior dorsal fin witli a strong spine; 

 mouth terminal, beak- shaped; dental plates and columns fused 

 with the jaws. 0]>tic nerves not decussating. Valves of bulbus 

 arteriosus multlserial. Gills laminar, with a small proportion of 



