NOTES ON EMBRYOLOGY AND CLASSIFICATION. 451 



Divisions of the HETERODACTYLA 

 Class I. — Pisces. 

 Subclass. Order. 



r 

 1. Squali 



I. Selachii 



II. HoLOCEPHALI 



III. Ganoids 



IV. Teleostei 



2. Raii 



"1. Sturiones 



2. Polypterini 



3. Lepidosteini . 



4. Amiadini 



5. Cephalaspidse . 



6. Placodermi 



7. Acanthodini . 



Examples, 

 [ Heptane lius. 

 \_Sqiiatlna, 

 J Raia. 

 \ Torpedo, 

 j Chimcera. 

 \_ Callorhynchus. 



Acipenser. 



Volyodon. 



Pohjpterus. 



Calamoicthys. 



Lepidosteus. 



Palceoniscus. 



Amia. 



Cepkalaspis. 



Pteraspis. 



Pterietkys. 



Coccosteus. 



Acanthodes. 



r 



8. Pycnodontidse 



9. Cselacanthini , 



10. Dipterini 

 Branch a. Pkysostomi 



Biplacanthus. Y ^ 



Pycnodon 

 Ptatysomus. 

 Coblacanthus. 

 f Holoptychius 

 \ Osteolepis. 



I 



1. Abdominales 



1. Auacanthini 



( Clupea, Salmo, 

 \ Esox, Cyprinus,Si- 

 \lwus, Mormyrus. 



2. Apodes . . I^^^^^f. (^^ger. 

 y_ (jrymnotus. 



Branch b. Physoclisti. 



f Gadus. 

 \Pleuronectes. 



i 2. PharjngognatM [f^^^ 



T Perca, Trigla, 



3. Acanthopteri . <j Zeus, Cydopterus, 

 \JLophms. 



Branch c. Pledognathi. 



1. Plectognathi . fOdracion. 

 \_jJiodon. 



Branch d. Lophobranchi. 



2. Lophobranchi. y%^!9nathus. 

 \_Jtiippocampv,s. 



VOL. XYII, NEW SEE. G G 



