proximating them, while, on the other hand, Dr. Giinther 1 has contended 

 for the union of the Ganoids, Dipnoans, and Elasmobranchiates into one 

 subclass, for which he has proposed the name Palaeichthyes. 



Oin Ganoidernes Begrsendsning og Inddeling, .... < Videnskabilige 



Meddelelser fra den naturhistoriske Forening i Kjftbenhavn, for Aaret 1863, 1869, 

 pp. 1-82. 



On the limits and classification of the Ganoids. .... < Annals and 



Magazine of Natural History, (London), 4th series, v. 7, 1871, pp. 329-339. 

 Dr. Liitken attaches primary importance to (1) the freedom or attachment of the 

 gills, and (2) the communication of the air bladder with the intestinal canal or ex- 

 clusion therefrom. 



He subordinates the subdivisions as follows : — 



Subclass A. Teleostei s. Eleptherobranchii. ¥ 



Order 1. Physoclisti s. Acanthopteri. 

 Order 2. Physostomi s. Malacopteri. 



Suborder a. Typici (including Cycloganoidei). 

 Suborder b. Ganoidei. 

 Suborder c. Sturiones. 

 Suborder d. Protopteri. 

 Subclass B. Chokdrostei s. Desmobranchii. 

 Order 3. Selachii. 

 Order 4. Cyclostomi. 

 Order 5. Branchiostomi. 



Incertae sedis. 

 Order 6. Placodermi. 



The above subclass Teleostei is equivalent to the order Branchiata of Pallas, and 

 the subclass Telostomi of Owen ; the subclass Chondrostei, to the class Ichthyodera 

 of Geoffroy St. Hilaire, the order Spiraculata of Pallas, and the order Placoidei of 

 Agassiz. 



6 Cope (Edward Drinker). Observations on the Systematic relations of the Fishes, 

 .... <The American Naturalist (Salem), v. 5, 1871, pp. 579-593; also, 

 (somewhat modified) < Proceedings of the American Association for the Ad- 

 vancement of Science, 1871 (1872), pp. 317-343. 

 Prof. Cope's primary divisions or subclasses of the class Pisces are as follows : — 



Subclass Holocephali. 

 Subclass Selachii. 

 Subclass Dipnoi. 

 Subclass Crossopterygia. 

 Subclass Actinopteri. 

 Tribe Chondrostei. 

 Tribe Physostomi. 



Order Giuglymodi (Lepidosteidae). 

 Order Halecomorphi (Amiidae). 



The succeeding orders of Physostomi aud the Physoclysti are all Teleosteans of 



Miiller. 



1 Giinther (Albert C. L. G.). The new Ganoid fish (Ceratodus) recently discovered 

 in Queensland. < Nature, (London.) v. 4, 1S71, pp. 406-408, 423-429, (447). 



